Journal articles on the topic 'Oestradiol/progesterone'
To see the other types of publications on this topic, follow the link: Oestradiol/progesterone.
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 journal articles for your research on the topic 'Oestradiol/progesterone.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.
1
Martel, D., M. N. Monier, D. Roche, V. J. De Feo, and A. Psychoyos. "Hormonal dependence of the metrial gland: further studies on oestradiol and progesterone receptor levels in the rat." Journal of Endocrinology 120, no. 3 (March 1989): 465–72. http://dx.doi.org/10.1677/joe.0.1200465.
Full textAbstract:
ABSTRACT The main objective of the present study was to analyse the hormonal dependence of the metrial gland formed in pseudopregnant animals following massive decidualization. On day 13 of pseudopregnancy (when the metrial gland reaches its maximal development) animals were ovariectomized and given s.c. implants of oestradiol and/or progesterone. A new implant technique for oestradiol delivery is described which provides circulating concentrations of oestradiol in the physiological range. In addition, we extended our previous work concerning oestradiol receptor and progesterone receptor concentrations in the metrial gland of pseudopregnant rats. The low oestradiol receptor concentration which we previously reported up to day 17 was maintained until the end of pseudopregnancy (day 21–1·5 fmol/μg DNA), whereas the progesterone receptor concentration remained raised (≃3·5 fmol/μg DNA) from day 13 to day 19 and then decreased on day 21. The correlation of metrial gland weight and kinetics of the tissue oestradiol and progesterone receptors contents with the circulating oestradiol and progesterone concentrations lead to the following conclusions. First, the maintenance of the metrial gland is strictly progesterone-dependent. It is unlike the deciduoma which regresses spontaneously, even in the presence of progesterone. Secondly, the production of oestradiol receptor, but not of progesterone receptor, appears to be repressed in the metrial gland under the influence of progesterone. Thus, the tissue retains its ability to respond to progesterone because of a high concentration of progesterone receptor. It is difficult to attribute this high tissue progesterone receptor concentration to oestradiol stimulation since, even at low levels, oestradiol induces tissue regression. We suggest that the high progesterone receptor concentration could be due to constitutive (basal) progesterone receptor production. Journal of Endocrinology (1989) 120, 465–472
2
Corbani, M., R. Counis, E. Wolinska-Witort, G. d'Angelo-Bernard, M. Moumni, and M. Jutisz. "Synergistic effects of progesterone and oestradiol on rat LH subunit mRNA." Journal of Molecular Endocrinology 4, no. 2 (April 1990): 119–25. http://dx.doi.org/10.1677/jme.0.0040119.
Full textAbstract:
ABSTRACT The effects of oestradiol and progesterone on LH-subunit mRNA levels were investigated in ovariectomized rats. Four weeks after ovariectomy, rats were implanted with silicone elastomer capsules containing oestradiol and/or injected daily with progesterone in oil (5 mg/rat) for 8 days. The levels of pituitary mRNA encoding α and LH-β were determined using direct hybridization with specific [32P]cDNA probes. After oestradiol implantation in ovariectomized rats, both α and LH-β mRNA decreased with time, with maximum inhibition after 6–8 days of treatment. Progesterone injected alone did not show any effect on α and LH-β mRNA. Cytosolic progesterone receptors, determined using [3H]methyl-17α-progesterone as ligand, were undectable in control ovariectomized rats. In contrast, 2 days after oestradiol implantation, the number of receptors increased to 287·5 ± 35·4 (s.e.m.) fmol/pituitary and reached a plateau of 400 ± 21·8 fmol/pituitary after 4 days. The effects of progesterone were therefore examined by first implanting ovariectomized rats with oestradiol to induce progesterone receptors and then injecting progesterone daily for a further period of 6 days. As a result of this treatment, progesterone induced a decrease in the pituitary gland contents of both α and LH-β mRNAs, and LH release was significantly greater than that observed in the group receiving oestradiol alone. Moreover, the mRNA levels in the animals treated with oestradiol plus progesterone were lower after 8 days of treatment than those observed in ovariectomized rats treated with a tenfold higher dose of oestradiol alone. These data demonstrate that progesterone, together with oestradiol, is capable of negatively regulating the mRNAs encoding subunits in vivo, provided that progesterone receptors are present in the pituitary gland.
3
Sizemore, R. J., P. R. Hurst, and B. J. McLeod. "Effect of steroid hormones on tissue remodelling and progesterone receptors in the uterus of seasonally anoestrous brushtail possums (Trichosurus vulpecula)." Reproduction 127, no. 2 (February 2004): 255–64. http://dx.doi.org/10.1530/rep.1.00091.
Full textAbstract:
This study describes progesterone receptor (PR) location within uterine cells and associated morphological changes to the uterine luminal and glandular epithelium in seasonally anoestrous brushtail possums treated with oestradiol and/or progesterone. Twenty-four adult female possums (n = 6/group) were treated with oestradiol, progesterone, oestradiol followed by progesterone or with the oil vehicle alone for 6-day periods. Uterine tissue was recovered, weighed and processed for light and transmission electron microscopy and for immunohistochemistry for PRs. Stereological techniques were used to quantify epithelial cell and constituent volumes for both luminal and glandular tissues. Plasma concentrations of oestradiol and progesterone were determined by radioimmunoassay. Mean uterine wet weights were significantly heavier (P < 0.001) following oestradiol/progesterone treatment and maximum gland dilation, cellular and stromal growth, maximum cell height, and cell and constituent volumes were recorded after this treatment regimen. Cell nuclei and debris were commonly observed in gland lumina, and nuclear PRs were found predominantly in stromal cells following oestradiol-only treatment. Sequential treatment with oestradiol and then progesterone caused a decline in the number of positively stained cells. Epithelial cells contained extensive secretory organelles and degenerating cells were common within the glands. Oestradiol treatment induced cell and cell constituent growth and promoted PR formation in anoestrous possum uterine tissue. Subsequent exposure to progesterone stimulated uterine tissues to reach maximum wet weights and led to the cellular maturation necessary to remodel the uterus in preparation for pregnancy.
4
MOREY, K. Anjali, Mahnaz RAZANDI, Ali PEDRAM, Ren-Ming HU, A. Bruce PRINS, and R. Ellis LEVIN. "Oestrogen and progesterone inhibit the stimulated production of endothelin-1." Biochemical Journal 330, no. 3 (March 15, 1998): 1097–105. http://dx.doi.org/10.1042/bj3301097.
Full textAbstract:
Important vascular proteins such as endothelin-1 (ET-1) promote the development of cardiovascular diseases. Oestrogen, and perhaps progesterone, prevent the development of vascular disease in women through incompletely understood cellular mechanisms. We hypothesized that oestradiol or progesterone might regulate the production of ET-1 as a potential novel mechanism. We found that serum and angiotensin II (AII) significantly stimulated ET-1 secretion from cultured bovine aortic endothelial cells, inhibited 50-75% by oestradiol or by progesterone. Serum and AII stimulated ET-1 mRNA levels, inhibited at least 70% by oestradiol and by progesterone. Serum stimulated ET-1 transcription mainly through the first 43 nucleotides of the ET-1 promoter, but oestradiol and progesterone did not inhibit this. In contrast, AII stimulated ET-1 transcription through nucleotides -143 to -98, specifically involving an activator protein-1 (AP-1) site at -102. Oestradiol and progesterone caused a 60-70% inhibition of AII-stimulated wild-type construct -.143ET-1/CAT activity (CAT is chloramphenicol acyltransferase). AII-stimulation of ET-1 transcription was critically dependent on stimulation of mitogen-activated protein kinase (erk) activity, inhibited by oestradiol and progesterone. In summary, we found that sex steroids inhibit AII-induced erk signalling to the ET-1 transcriptional programme. This novel mechanism of negative transcriptional regulation by oestradiol and progesterone decreases the production of ET-1, potentially contributing to the vascular protective effects of these steroids.
5
Saumande, J., and S. K. Batra. "Superovulation in the cow: comparison of oestradiol-17β and progesterone patterns in plasma and milk of cows induced to superovulate; relationships with ovarian responses." Journal of Endocrinology 107, no. 2 (November 1985): 259–64. http://dx.doi.org/10.1677/joe.0.1070259.
Full textAbstract:
ABSTRACT Free oestradiol-17β, free+conjugated oestradiol-17β (total oestradiol-17β) and progesterone in milk, and free oestradiol-17β and progesterone in plasma were measured in 16 cyclic cows injected with FSH to induce superovulation during the treatment and periovulatory periods. The patterns of steroid secretion were the same in milk as in plasma but at different concentrations. Among oestrogens, the highest concentrations were measured for total oestradiol-17β in milk, followed by free oestradiol in plasma and free oestradiol in milk. Progesterone concentrations in milk were higher than in plasma. The peak concentrations of oestrogens were related to ovulation rate: Spearman Rank Correlation coefficient (r.s.) = 0·87 (P < 0·001), 0·78 (P < 0·001) and 0·69 (P < 0·001) for total oestradiol, free oestradiol in milk and free oestradiol in plasma respectively. The increase in progesterone concentrations in milk between the beginning of treatment and prostaglandin injection was negatively correlated with the percentage of viable embryos among those recovered (r.s. = −0·68; P < 0·001). This was not observed for progesterone in plasma. These results therefore show that the steroid pattern in milk gives a better indication as to the ovarian response to a superovulatory treatment than does the steroid pattern in plasma. In addition the fact that milk samples are easier to obtain and handle than blood plasma have led us to conclude that, to follow the effect of gonadotrophin stimulation, it would be more informative to assay oestradiol-17β and progesterone in milk rather than in plasma. J. Endocr. (1985) 107, 259–264
6
Wiqvist, Ingrid, and Anders Linde. "Influence of steroid hormones on the incorporation of amino acids in uterine and cervical tissue of pregnant women." Acta Endocrinologica 115, no. 4 (August 1987): 537–43. http://dx.doi.org/10.1530/acta.0.1150537.
Full textAbstract:
Abstract. The influence of steroids on protein synthesis in cervical and uterine tissue obtained from early and term pregnant women was studied by measuring the incorporation of labelled amino acids into total protein. It was found that oestradiol-17β and progesterone significantly reduced the incorporation of [3H]proline. Androstenedione and cortisol had no significant effect on the incorporation of [3H]proline even at high concentrations. The protein synthesis inhibitors puromycin and cycloheximide blocked the incorporation of [3H]proline to 80–85%. However, there was no further reduction in the incorporation in the presence of oestradiol. Oestradiol was found to reduce the incorporation of [14C]glycine but not that of [3H]serine. The results indicate that oestradiol and progesterone reduce protein synthesis in human cervical and uterine tissue and that this reduction, at least partially, involves collagen synthesis. Oestradiol and progesterone were equipotent under in vitro experimental conditions. The tissue concentration of progesterone in the pregnant uterus is, however, much higher than that of oestradiol. It seems therefore probable that progesterone rather than oestradiol restricts unopposed synthesis of proteins, presumably mainly collagen.
7
Anderson, P. J. B., K. W. Hancock, and R. E. Oakey. "Non-protein-bound oestradiol and progesterone in human peripheral plasma before labour and delivery." Journal of Endocrinology 104, no. 1 (January 1985): 7–15. http://dx.doi.org/10.1677/joe.0.1040007.
Full textAbstract:
ABSTRACT Plasma samples were obtained at weekly intervals from the peripheral circulation of 12 women in the last 2–7 weeks of pregnancy. The concentrations of oestradiol and progesterone (isolated by chromatography) were measured by radioimmunoassay; the proportion of each hormone which was not bound to protein was measured by steady-state gel filtration. From these, the apparent concentration of the non-protein-bound form of each hormone was calculated. The mean proportion of oestradiol not bound to protein varied from 0·84 to 2·71% in the different subjects, but within each subject variation was within experimental error. For progesterone, the mean proportion not bound to protein in the different subjects varied from 1·76 to 2·77%; within individuals the proportion remained essentially constant. There was no consistent, recognizable trend as labour approached in (i) the concentration of oestradiol; (ii) the concentration of progesterone; (iii) the concentrations of non-protein-bound oestradiol or non-protein-bound progesterone; (iv) the ratio of the concentrations of progesterone and oestradiol; (v) the ratio of the concentrations of non-protein-bound progesterone and oestradiol. In nine out of 12 subjects, the ratio of the concentration of non-protein-bound progesterone to that of non-protein-bound oestradiol was greater than the corresponding ratio based on total hormone concentrations. These results therefore provide no support for the hypothesis that human labour is preceded by alteration in the progesterone to oestradiol ratio which can be detected by measurement of these hormones in peripheral blood. J. Endocr. (1985) 104, 7–15
8
Ortmann, O., K. Johannsen, R. Knuppen, and G. Emons. "Acute effects of oestradiol and progesterone on melittin- and gonadotrophin-releasing hormone-induced LH secretion." Journal of Endocrinology 132, no. 2 (February 1992): 251–59. http://dx.doi.org/10.1677/joe.0.1320251.
Full textAbstract:
ABSTRACT It is well established that oestradiol and progesterone modulate gonadotrophin-releasing hormone (GnRH)-induced LH secretion from cultured rat pituitary cells. Short-term oestradiol and long-term progesterone treatment exert inhibition, while short-term progesterone and long-term oestradiol treatment lead to enhancement of GnRH-stimulated LH secretion. There are several lines of evidence to suggest that the steroid effects might be mediated via a mechanism involving modulation of the GnRH signal-transduction system. To evaluate the role of arachidonic acid, which serves as an intracellular signal transducer by itself or its lipoxygenase metabolites, in the mediation of oestradiol and progesterone actions, we examined their effects on melittin (activator of phospholipase A2)-stimulated LH secretion. When pituitary cells from adult female rats were treated for 48 h with 1 nmol oestradiol/l or 1 nmol oestradiol/l plus 100 nmol progesterone/l, GnRH (1 nmol/l)-induced LH secretion was stimulated or inhibited respectively. However, melittin (10–300 nmol/l)-stimulated LH secretion remained unaffected after such treatment. Short-term treatment with oestradiol inhibited GnRH-induced LH secretion while progesterone treatment of oestradiol-primed cells led to a stimulatory effect. Interestingly, melittin-stimulated LH secretion was influenced in the same way after the short treatment paradigm. Perifusion studies were performed to assess the kinetics of these acute steroid actions further. Four separate perifusion chambers were continuously perifused with medium and stimulated for 2 min with 1 nmol GnRH/l or 1 μmol melittin/l every 50 min in a pulsatile fashion. When 1 nmol oestradiol/l was added to the perifusion medium after the application of an initial control pulse, GnRH- and melittin-stimulated LH secretion were inhibited by 69 and 61% respectively. This effect was present after 50 min. When oestradiol-primed cells were treated with 100 nmol progesterone/l starting after the initial GnRH or melittin pulse, an acute stimulatory effect was observed in response to both stimuli after 50 min. LH release was enhanced by up to 279 (GnRH) or 419% (melittin) compared with the control pulse. The kinetics of inhibited or stimulated pulsatile LH secretion were virtually identical when GnRH or melittin were used as stimuli. These results demonstrate that short-term oestradiol or progesterone treatment modulate arachidonic acid-mediated LH secretion in a similar fashion to GnRH-induced LH secretion, while long-term oestradiol or progesterone treatment only affected GnRH-induced LH secretion. Journal of Endocrinology (1992) 132, 251–259
9
Carey, M. P., C. H. Deterd, J. de Koning, F. Helmerhorst, and E. R. de Kloet. "The influence of ovarian steroids on hypothalamic-pituitary-adrenal regulation in the female rat." Journal of Endocrinology 144, no. 2 (February 1995): 311–21. http://dx.doi.org/10.1677/joe.0.1440311.
Full textAbstract:
Abstract The present study examined the association between hypothalamic-pituitary-adrenal (HPA) and hypothalamic-pituitary-ovarian axes. HPA activity determined by plasma levels of adrenocorticotropin (ACTH) and corticosterone (B) was assessed in intact female rats as a function of oestrous cycle stage under resting conditions and after exposure to a 20 min restraint stress. To delineate the roles of oestradiol and progesterone in HPA axis modulation, plasma concentrations of ACTH and B were determined in ovariectomised (OVX) animals treated with oestradiol and/or progesterone under resting conditions and during exposure to the stress of a novel environment. The effects of these steroid treatments on the transcription and/or binding properties of the two corticosteroid receptors, the mineralocorticoid (MR) and glucocorticoid (GR) receptors, were also examined in hippocampal tissue. (i) Fluctuations in basal and stress-induced plasma ACTH and B concentrations were found during the oestrous cycle with highest levels at late pro-oestrus. (ii) In OVX steroid-replaced animals, basal and stress-induced activity was enhanced in oestradiol and oestradiol plus progesterone-treated animals compared with OVX controls. (iii) Cytosol binding assays revealed an oestradiol-induced decrease in hippocampal MR capacity. This decrease appears to be due to an effect of the steroid on MR transcription as in situ hybridisation analysis of MR mRNA showed an oestradiol-induced decrease in MR transcript in all hippocampal subfields. (iv) Treatment of oestradiol-primed animals with progesterone reversed the oestradiol-induced decrease in hippocampal MR capacity. Data from MR mRNA hybridisation in situ experiments indicate that this reversal may be due to an antagonism of the oestradiol effect on MR transcription. (v) Progesterone treatment with or without prior oestradiol-priming induced a significant decrease in the apparent binding affinity of hippocampal MR. We show that progesterone and its 11 β-hydroxylated derivative have a high affinity for the hippocampal MR. (vi) Neither oestradiol nor progesterone affected GR binding parameters in the hippocampus. In conclusion, we find that sex steroids modulate HPA activity and suggest that the observed effects of these steroids on hippocampal MR may underlie their concerted mechanism of action in inducing an enhanced activity at the period of late pro-oestrus. Journal of Endocrinology (1995) 144, 311–321
10
Wathes, D. C., G. E. Mann, J. H. Payne, P. R. Riley, K. R. Stevenson, and G. E. Lamming. "Regulation of oxytocin, oestradiol and progesterone receptor concentrations in different uterine regions by oestradiol, progesterone and oxytocin in ovariectomized ewes." Journal of Endocrinology 151, no. 3 (December 1996): 375–93. http://dx.doi.org/10.1677/joe.0.1510375.
Full textAbstract:
Abstract The regulation of oxytocin, oestradiol and progesterone receptors in different uterine cell types was studied in ovariectomized ewes. Animals were pretreated with a progestogen sponge for 10 days followed by 2 days of high-dose oestradiol to simulate oestrus. They then received either low-dose oestradiol (Group E), low-dose oestradiol plus progesterone (Group P) or low-dose oestradiol, progesterone and oxytocin (via osmotic minipump; Group OT). Animals (three to six per time-point) were killed following ovariectomy (Group OVX), at oestrus (Group O) or following 8, 10, 12 or 14 days of E, P or OT treatment. In a final group, oxytocin was withdrawn on day 12 and ewes were killed on day 14 (Group OTW). Oxytocin receptor concentrations and localization in the endometrium and myometrium were measured by radioreceptor assay, in situ hybridization and autoradiography with the iodinated oxytocin receptor antagonist d(CH2)5[Tyr(Me)2,Thr4,Tyr-NH29]-vasotocin. Oestradiol and progesterone receptors were localized by immunocytochemistry. Oxytocin receptors were present in the luminal epithelium and superficial glands of ovariectomized ewes. In Group O, endometrial oxytocin receptor concentrations were high (1346 ± 379 fmol [3H]oxytocin bound mg protein−1) and receptors were also located in the deep glands and caruncular stroma in a pattern resembling that found at natural oestrus. Continuing low-dose oestradiol was unable to sustain high endometrial oxytocin receptor concentrations with values decreasing significantly to 140 ± 20 fmol mg protein−1 (P<0·01), localized to the luminal epithelium and caruncular stroma but not the glands. Progesterone treatment initially abolished all oxytocin receptors with none present on days 8 or 10. They reappeared in the luminal epithelium only between days 12 and 14 to give an overall concentration of 306 ± 50 fmol mg protein−1. Oxytocin treatment caused a small increase in oxytocin receptor concentration in the luminal epithelium on days 8 and 10 (20 ± 4 in Group P and 107 ± 35 fmol mg protein−1 in Group OT, P<0·01) but the rise on day 14 was not affected (267 ± 82 in Group OT and 411 ± 120 fmol mg protein−1 in Group OTW). In contrast, oestradiol treatment was able to sustain myometrial oxytocin receptors (635 ± 277 fmol mg protein−1 in Group O and 255 ± 36 in Group E) and there was no increase over time in Groups P, OT and OTW with values of 61 ± 18, 88 ± 53 and 114 ± 76 fmol mg protein−1 respectively (combined values for days 8–14). Oestradiol receptor concentrations were high in all uterine regions in Group O. This pattern and concentration was maintained in Group E. In all progesterone-treated ewes, oestradiol receptor concentrations were lower in all regions at all time-points. The only time-related change occurred in the luminal epithelium in which oestradiol receptors were undetectable on day 8 but developed by day 10 of progesterone treatment. Progesterone receptors were present at moderate concentrations in the deep glands, caruncular stroma, deep stroma and myometrium in Group O. Oestradiol increased progesterone receptors in the luminal epithelium, superficial glands, deep stroma and myometrium. Progesterone caused the loss of its own receptor from the luminal epithelium and superficial glands and decreased its receptor concentration in the deep stroma and myometrium at all time-points. There was a time-related loss of progesterone receptors from the deep glands of progesterone-treated ewes between days 8 and 14. These results show differences in the regulation of receptors between uterine regions. In particular, loss of the negative inhibition by progesterone on the oxytocin receptor by day 14 occurred only in the luminal epithelium, but is unlikely to be a direct effect of progesterone as no progesterone receptors were present on luminal epithelial cells between days 8 and 14. The presence of oxytocin receptors in the luminal epithelium of ovariectomized ewes suggests that oestradiol is not essential for oxytocin receptor synthesis at this site. Oestradiol was able to sustain its own receptor at all sites, but high circulating progesterone was always inhibitory to oestradiol receptors. In general, oestradiol stimulated progesterone receptors in epithelial cells whereas progesterone abolished its own receptor from epithelial cells over a period of time, but had a lesser effect on stromal cells. The concentration of all three receptors is therefore differentially regulated between different uterine cell types, suggesting the importance of paracrine effects which remain to be elucidated. Journal of Endocrinology (1996) 151, 375–393
11
Elliott, Ruth A., and C. M. Castleden. "Effect of Progestogens and Oestrogens on the Contractile Response of Rat Detrusor Muscle to Electrical Field Stimulation." Clinical Science 87, no. 3 (September 1, 1994): 337–42. http://dx.doi.org/10.1042/cs0870337.
Full textAbstract:
1. The effect of oestradiol and progesterone pre-treatment on the contractile response of isolated rat detrusor muscle to electrical field stimulation was investigated. The response to direct administration of 2 μmol/l progesterone and 2 μmol/l diethylstilboestrol in the organ bath was also examined. 2. Virgin female Wistar rats were injected sub-cutaneously with oestradiol benzoate (150 μg/kg) for 3 days followed by 1 day of progesterone (160 μg/kg). This cycle was repeated once. Control rats received no injections. 3. In controls, progesterone significantly reduced the maximum contractile response of rat detrusor muscle in vitro by 12% (P < 0.01). The EF50 was significantly increased compared with control. When 2 μmol/l diethylstilboestrol, was added, the maximum contractile response was significantly reduced by 42% (P < 0.01) and the frequency-response curve showed a further increase in EF50. 4. Progesterone had no effect on the atropine-resistant component of electrical field stimulation, but progesterone and diethylstilboestrol reduced the atropine-resistant response by 16% (P < 0.01). 5. Detrusor muscle from pretreated rats showed a non-significant increase in maximum contractile response compared with untreated controls. The addition of 2 μmol/l progesterone to the bath chamber had no effect on this response, but the further addition of 2 μmol/l diethylstilboestrol reduced the maximum contraction. 6. Pretreatment with oestradiol and progesterone had no effect on the atropine- or tetrodotoxin-sensitive response to electrical field stimulation. 7. In conclusion, the direct effect of progesterone and diethylstilboestrol inhibited the contractile response of detrusor muscle to electrical field stimulation and the effects of each summated. Atropine blocked this effect of progesterone, but not that of diethylstilboestrol. Pretreatment with progesterone and oestradiol had no significant effect on rat detrusor contractile response. Since treatment with oestradiol alone has been shown to have a significant inhibitory action on contractile response, the addition of progesterone would appear to alter this effect of oestradiol.
12
MANALU, W., and M. Y. SUMARYADI. "Correlations between lamb birth weight and the concentrations of hormones and metabolites in the maternal serum during pregnancy." Journal of Agricultural Science 133, no. 2 (September 1999): 227–34. http://dx.doi.org/10.1017/s0021859699006887.
Full textAbstract:
Maternal serum hormones (progesterone, oestradiol, triiodothyronine and cortisol) and blood metabolites (β-hydroxy butyric acid [BHBA] and blood urea nitrogen [BUN]) concentrations at weeks 0, 4, 8, 12, 16 and 20 of pregnancy were measured in 39 pregnant Javanese thin-tail ewes (20 and 19 carrying single and multiple [2–3] foetuses, respectively), and six non-pregnant ewes as controls, to evaluate their correlations with lamb birth weight at parturition. All hormones and metabolites changed with the advance of pregnancy. Regression analyses showed that concentrations of triiodothyronine, cortisol, BHBA, and BUN in the maternal circulation during pregnancy had lower correlations with lamb birth weight at parturition than those of progesterone and oestradiol. Progesterone and oestradiol concentrations in the maternal circulation at week 8 of pregnancy had the greatest correlations with lamb birth weight at parturition. The higher the concentrations of progesterone and oestradiol in the maternal circulation at week 8 of pregnancy, the higher the lamb birth weight at parturition. The results suggested that raising maternal serum progesterone and oestradiol concentrations during early pregnancy in sheep, either by exogenous administration or superovulation, might improve prenatal growth and lamb birth weight.
13
Chaminadas, G., M. Alkhalaf, J. P. Rémy-Martin, A. Y. Propper, and G. L. Adessi. "Specific effect of oestrone sulphate on protein synthesis and secretion by cultured epithelial cells from guinea-pig endometrium." Journal of Endocrinology 123, no. 2 (November 1989): 233—NP. http://dx.doi.org/10.1677/joe.0.1230233.
Full textAbstract:
ABSTRACT Patterns of induced protein synthesis and secretion in guinea-pig endometrial epithelial cell cultures in response to oestrone sulphate alone and oestrone sulphate plus progesterone were investigated. Epithelial cells were cultured for 3 days in growth medium, then washed three times in a steroid-free medium. For each experiment, anticytokeratin immunostaining was used to discriminate the epithelial cells from the stromal cells. Only experiments in which the control dishes displayed more than 80% of anticytokeratinimmunostained cells were further processed. After this period oestradiol-17β (20 nmol/l; control), oestradiol-17β (20 nmol/l) plus progesterone (0·5 μmol/l), oestrone sulphate (1 μmol/l) or oestrone sulphate (1 μmol/l) plus progesterone (0·5 μmol/l) were added to the medium for 48 h. An immunocytochemical progesterone receptor assay showed that oestradiol-17β increased the progesterone receptor content of cells, and progesterone added to cultured cells in the presence of oestradiol-17β induced a significant increase in oestrogen sulphotransferase activity assessing the hormone responsiveness of the cultured cells. In these culture conditions and after 16 h of incubation, oestradiol-17β induced a 1·7-fold increase in [3H]thymidine incorporation into DNA, and [35S]methionine incorporation into cellular proteins was linearly increased up to 8 h. Biochemical changes induced by the different hormone treatments were studied by labelling the proteins with a 6-h pulse of [35S]methionine. The proteins present in the medium and in cells were analysed by two-dimensional polyacrylamide gel electrophoresis, followed by fluorography. Addition of oestrone sulphate alone or with progesterone produced a change in the patterns of cellular and secreted proteins compared with those in cells cultured with either oestradiol-17β or oestradiol-17β plus progesterone. Three cellular proteins (Mr < 14 000, isoelectric point (pI) 5·2 and 5·3; Mr 75 000, pI 4·9) and one secreted protein (Mr 155 000, pI 5·6–5·9) were specifically induced and could serve as markers of oestrone sulphate action. Journal of Endocrinology (1989) 123, 233–241
14
Curlewis, J. D., M. Axelson, and G. M. Stone. "Identification of the major steroids in ovarian and adrenal venous plasma of the brush-tail possum (Trichosurus vulpecula) and changes in the peripheral plasma levels of oestradiol and progesterone during the reproductive cycle." Journal of Endocrinology 105, no. 1 (April 1985): 53–62. http://dx.doi.org/10.1677/joe.0.1050053.
Full textAbstract:
ABSTRACT The quantitatively major steroid hormones in ovarian and adrenal venous plasma of the female brush-tail possum were identified by gas chromatography–mass spectrometry. The ovarian vein plasma samples all contained oestradiol and its concentration was highest during the pro-oestrous phase of the reproductive cycle. During this phase the concentration of progesterone was below the limit of detection but at day 13 of the oestrous cycle and pregnancy, the concentration of progesterone exceeded that of oestradiol. Cortisol and corticosterone were the major steroid hormones found in all adrenal vein samples with cortisol predominant. Androgens with a 3-oxo structure, if present, were below the limits of detection in all plasma samples. Radioimmunoassays for the measurement of progesterone and oestradiol in peripheral plasma were used to follow changes in the concentrations of these steroids during the reproductive cycle. Progesterone in serial blood samples was low at oestrus, rose gradually until day 7 and then increased more rapidly to reach a peak level of 21–29 nmol/l at around day 13. Any differences between the pregnant and non-pregnant cycles were minor. Oestradiol was only detected around oestrus when levels were variable (53·3±20·92 (s.e.m.) pmol/l; n = 4). The results indicate that the reproductive cycle of the brush-tail possum is characterized by a single peak of oestradiol at around pro-oestrus followed by gradually increasing levels of progesterone. Pregnancy appears to have no influence on the circulating concentrations of oestradiol or progesterone. J. Endocr. (1985) 105, 53–62
15
Kaminski, M. A., S. H. Hayes, and W. J. Silvia. "Effects of progesterone withdrawal on uterine secretion of prostaglandin F2α in response to oxytocin in ewes." Reproduction, Fertility and Development 9, no. 2 (1997): 255. http://dx.doi.org/10.1071/r96056.
Full textAbstract:
Two experiments were conducted to determine if withdrawal of progesterone during the luteal phase of the oestrous cycle affected the ability of the ovine uterus to secrete prostaglandin F2α(PGF2α ) in response to oxytocin. In Experiment 1, 18 ewes were ovariectomized on Day 9 and Day 12 after oestrus. Ewes were subdivided into three treatment groups (n= 6 per group): Group-1 ewes underwent sham surgery; Group-2 ewes received oestradiol (OVX + O); and Group-3 ewes received oestradiol + progesterone (OVX + O,P). Oxytocin was administered to each ewe on Days 10, 13 and 15 after oestrus. Concentrations of 13,14-dihydro-15-keto-PGF2α (PGFM) were determined in samples of jugular venous blood for 2 h after oxytocin challenge. The magnitude of the PGFM response 24 h after ovariectomy was greater (P < 0·1) in ewes from which progesterone had been withdrawn (OVX + O) than in ewes in which progesterone was maintained (intact controls and OVX + O,P). Therefore, progesterone appears to exert an inhibitory effect on uterine secretory responsiveness to oxytocin which is removed by progesterone withdrawal. In Experiment 2, ewes were ovariectomized on Day 11 and assigned to 1 of 4 treatment groups (n = 6 per group): Group 1, no steroid replacement (OVX); Group 2, oestradiol replacement (OVX + O); Group 3, progesterone replacement (OVX + P); or Group 4, progesterone+oestradiol replacement (OVX + O,P). Ewes received oxytocin on Day 12 and Day 15. On Day 12, uterine secretory responsiveness to oxytocin was greatest in ewes in the OVX + O group (P < 0 · 1). Responsiveness was low in ewes in the OVX group, as it was in ewes in both groups that received progesterone replacement. Therefore, the increase in uterine secretory responsiveness to oxytocin following progesterone withdrawal is dependent on oestradiol replacement.
16
Alkhalaf, M., G. Chaminadas, A. Y. Propper, and G. L. Adessi. "Ultrastructural changes induced by oestradiol-17β, progesterone and oestrone-3-sulphate in guinea-pig endometrial glandular cells grown in primary culture." Journal of Endocrinology 122, no. 2 (August 1989): 439—NP. http://dx.doi.org/10.1677/joe.0.1220439.
Full textAbstract:
ABSTRACT The effects of oestradiol-17β, progesterone and oestrone-3-sulphate were studied in primary cultures of guinea-pig endometrial glandular epithelial cells. Comparative ultrastructural studies were performed by means of transmission electron microscopy on cells grown either without hormones or with oestradiol-17β (2 nmol/l), oestradiol-17β (2 nmol/l) plus progesterone (50 nmol/l), or oestrone sulphate (0·1 μmol/l). In the control medium, without steroid hormones, the majority of epithelial cells were poorly differentiated, although numerous small mitochondria were present and abundant lipid droplets could be observed. Oestradiol-17β stimulated metabolic activity in the cells. Progesterone added to oestradiol-17β-primed cells stimulated the development of the endoplasmic reticulum–Golgi system. Oestrone sulphate induced a higher level of differentiation characterized by large clear mitochondria, well-developed Golgi complexes, and active nuclei, suggesting secretory activity. In all cases, the cultured cells displayed deep invaginations of the nuclear membrane associated with nuclear pores, known as nucleolar channels. After treatment with oestrone sulphate these channels were associated with a characteristic reticular nucleolus. We conclude that cultured endometrial epithelial cells display secretory activity in response to treatment with oestradiol-17β plus progesterone, or with oestrone sulphate. Journal of Endocrinology (1989) 122, 439–444
17
Ogando, D., M. Farina, M. L. Ribeiro, S. Perez Martinez, M. Cella, V. Rettori, and A. Franchi. "Steroid hormones augment nitric oxide synthase activity and expression in rat uterus." Reproduction, Fertility and Development 15, no. 5 (2003): 269. http://dx.doi.org/10.1071/rd03013.
Full textAbstract:
Nitric oxide (NO) is synthesized in a variety of tissues, including rat uterus, from L-arginine by NO synthase (NOS), of which there are three isoforms, namely neuronal, endothelial and inducible NOS (nNOS, eNOS and iNOS, respectively). Nitric oxide is an important regulator of the biology and physiology of the organs of the reproductive system, including the uterus. Some studies have shown increased variation in NO production and NOS expression during the oestrous cycle. However, the factors that regulate NO production in the uterus remain unclear. Therefore, in the present study, we investigated the effect of sex steroids on NOS expression and activity in the ovariectomized rat uterus. Ovariectomized rats received progesterone (4 mg per rat) or 17β-oestradiol (1 μg per rat). All rats were killed 18 h after treatment. Both progesterone and oestradiol were able to augment NOS activity. The effect of oestradiol was abolished by pre-incubation with 500 μM aminoguanidine, an iNOS inhibitor, or by coadministration of oestradiol with 3 mg kg−1 dexamethasone, but the effect of progesterone was not affected by these treatments. Uterine nNOS, eNOS and iNOS protein levels were assessed using Western blots. Ovariectomized rat uteri expressed iNOS and eNOS. Progesterone increased the expression of eNOS and iNOS, whereas oestradiol increased iNOS expression only. These results suggest that oestradiol and progesterone are involved in the regulation of NOS expression and activity during pregnancy and implantation in the rat.
18
Kalison, B., M. L. Warshaw, and G. Gibori. "Contrasting effects of prolactin on luteal and follicular steroidogenesis." Journal of Endocrinology 104, no. 2 (February 1985): 241–50. http://dx.doi.org/10.1677/joe.0.1040241.
Full textAbstract:
ABSTRACT To determine whether prolactin affects both luteal and follicular production of testosterone and oestradiol, pseudopregnant rats, either intact or hypophysectomized on day 8, were injected daily between days 8 and 9 with 1·5 i.u. human chorionic gonadotrophin (hCG), 250 μg prolactin or a combination of both. Control rats were given vehicle. On day 9, blood was obtained from the ovarian vein and corpora lutea and follicles were isolated and incubated in vitro for 2 h. Administration of hCG to intact rats increased ovarian secretion of testosterone and oestradiol dramatically, but did not affect progesterone secretion. Hypophysectomy on day 8 of pseudopregnancy was followed by a drop in ovarian steroid secretion. Prolactin treatment of hypophysectomized rats markedly enhanced progesterone production but had no stimulatory effect on either testosterone or oestradiol. In contrast, hCG dramatically enhanced ovarian secretion of both testosterone and oestradiol without affecting progesterone secretion. Prolactin administered together with hCG antagonized the stimulation of both testosterone and oestradiol secretion by hCG, yet increased progesterone production. When the specific effects of hCG and prolactin administration on follicles and corpora lutea were studied separately, it was found that hCG treatment in vivo greatly stimulated testosterone and oestradiol production by both tissues in vitro. Since hCG only marginally affected aromatase activity in the follicle, had no effect on aromatase activity in luteal cells and did not increase progesterone synthesis, it appears that hCG acts to increase the formation of androgen substrate for oestradiol biosynthesis. Prolactin, administered with or without hCG, inhibited both basal and hCG-stimulated testosterone and oestradiol synthesis by the follicle. In sharp contrast to its inhibitory effect on follicular production of steroids, prolactin appears to be essential for LH stimulation of testosterone and oestradiol by the corpus luteum. In the absence of prolactin, luteal cells gradually ceased to respond to LH and decreased their output of testosterone and oestradiol. Prolactin administration to hypophysectomized rats did not affect luteal cell production of either steroid. However, corpora lutea of rats treated with prolactin responded to the hCG challenge with an increase in testosterone and oestradiol synthesis. In summary, results of this investigation demonstrate that prolactin affects follicular and luteal production of testosterone and oestradiol in opposite ways. It acts on the follicle to inhibit both basal and LH-stimulated production of testosterone and oestradiol, yet it markedly enhances LH stimulation of testosterone and oestradiol synthesis by luteal cells. J. Endocr. (1985) 104, 241–250
19
Laherty, Richard F., Daniel Rotten, May Yamamoto, and Robert B. Jaffe. "Effects of oestradiol and prolactin on progesterone production by rhesus monkey luteal cells in vitro." Acta Endocrinologica 108, no. 2 (February 1985): 266–72. http://dx.doi.org/10.1530/acta.0.1080266.
Full textAbstract:
Abstract. The effects of oestradiol and prolactin (Prl) on progesterone production by dispersed monkey luteal cells were examined. Corpora lutea were recovered from monkeys 5–7 days following ovulation induction during the puerperium. The tissue was dispersed by collagenase and mechanical disruption. The resulting cells were incubated in Dulbecco's modified Eagle's medium, containing the hormones to be tested, for 3 h at 37°C. The medium was removed and assayed for progesterone by RIA. Human luteinizing hormone (hLH) produced a significant, dose-related increase in progesterone secretion that was comparable to that produced by dibutyryl cyclic adenosine monophosphate. Human follicle stimulating hormone (hFSH) had no effect upon progesterone production by the luteal cells. Oestradiol (100–10 000 pg/ml) produced a significant, dose-related decrease in both basal and hLH-stimulated progesterone production. Ovine Prl (oPrl) had neither a stimulatory nor an inhibitory effect upon basal progesterone secretion at doses up to 1000 ng/ml. Further, oPrl did not affect hLH-stimulated progesterone production. We conclude that oestradiol is a potent inhibitor of luteal progesterone secretion in vitro and that Prl does not inhibit progesterone production in the primate corpus luteum under these experimental conditions.
20
Lustig, R. H., D. W. Pfaff, and J. Fishman. "Opioidergic modulation of the oestradiol-induced LH surge in the rat: roles of ovarian steroids." Journal of Endocrinology 116, no. 1 (January 1988): 55–69. http://dx.doi.org/10.1677/joe.0.1160055.
Full textAbstract:
ABSTRACT Sex steroids convey information on the status of the reproductive system, which the brain is able to integrate to promote ovulation, in the form of the LH surge. The present studies examined the influence of alterations in central opioidergic tone to initiate the LH surge, and the roles of oestradiol and progesterone to effect changes in opioidergic tone, by antagonizing this activity using either naloxone or nalmefene (N-cyclopropylmethyl-6-desoxy-6-methylene-noroxymorphone), a long-acting μ- and κ-opiate antagonist. The timing and amplitude of the LH surge was examined in (1) cyclic rats in pro-oestrus and (2) ovariectomized rats with varying doses of oestradiol supplementation. Plasma was obtained hourly through an indwelling intra-atrial catheter between 13.00 and 19.00 h, and later assayed for LH and oestradiol concentrations by radioimmunoassay. Rats treated with either nalmefene or progesterone on pro-oestrus demonstrated similar advances in the time of initiation of the LH surge by 1–2 h compared with control rats. The effects of nalmefene and progesterone were evident within 2 and 3–5 h of their administration respectively. Conversely, rats treated with progesterone on dioestrus demonstrated low prooestrous oestradiol levels and abolition of the prooestrous LH surge, but continuous naloxone infusion restored the pro-oestrous LH surge, with raised oestradiol concentrations. In ovariectomized rats without oestradiol supplentation, nalmefene alone was able to increase basal LH levels, but unable to facilitate a spontaneous rise in LH amplitude indicative of an LH surge. Supplementation with low doses of oestradiol was itself ineffective in facilitating a spontaneous rise in LH concentration, but nalmefene co-administration significantly potentiated the ability of low doses of oestradiol to induce augmented LH secretion, in addition to advancing the timing of the spontaneous LH rise. Similarly, progesterone co-administration to ovariectomized, oestradiol-primed rats significantly advanced and augmented LH hypersecretion. The results of these experiments are consistent with the concept that central opioidergic systems normally restrain the initiation of the LH surge, and that blocking opiate receptors removes this inhibition. They advance the hypothesis that oestradiol, the essential signal for LH surge induction, has, as one consequence of its action, the time-specific inhibition of hypothalamic opioidergic tone in the afternoon, which would otherwise restrain the LH surge-generating mechanism. Finally, the biphasic effect of progesterone on the LH surge appears to be mediated through dichotomous actions on opioidergic tone; in the highoestrogen state, progesterone advances LH surge timing, mimicking the effect of an opiate antagonist, but in the low-oestrogen state, progesterone abolishes the subsequent LH surge, and its effect is negated by an opiate antagonist. J. Endocr. (1988) 116, 55–69
21
BECEDAS, Luisa, Bo LUNDGREN, and Joseph W. De PIERRE. "Characterization of the UDP-glucuronosyltransferase isoenzyme expressed in rat ovary and its regulation by gonadotropins." Biochemical Journal 332, no. 1 (May 15, 1998): 51–55. http://dx.doi.org/10.1042/bj3320051.
Full textAbstract:
Earlier studies have demonstrated that phenol UDP-glucuronosyltransferase (UGT) activity is up-regulated by pregnant mare's serum gonadotropin (PMSG) in rat ovary, but not liver. This phenomenon was investigated in more detail in the present study. Ovaries and livers of immature rats, rats synchronized with respect to their preovulatory and corpus lutealphases by treatment with PMSG, and mature rats hyperstimulated with PMSG were compared. Under all of these conditions, only one immunoreactive band of UGT, shown to be phenol UGT, was detected in the rat ovary. The effects of oestradiol, progesterone and/or human chorionic gonadotropin (hCG) on the level of phenol UGT in immature rat ovary were also examined. Partial up-regulation was caused by progesterone or oestradiol, together with hCG, whereas progesterone or oestradiol alone had no up-regulating effect. Follicle-stimulating hormone also seemed to be required for the up-regulation in ovaries enriched in corpus luteum. The present findings demonstrate that progesterone is involved in the regulation of phenol UGT in rat ovary by gonadotropins. Regulation by both progesterone and oestradiol was dependent on induction of ovulation and steroidogenesis by luteinizing hormone.
22
Tang, Pei-Zhong, Michael J. Gannon, Alison Andrew, and David Miller. "Evidence for oestrogenic regulation of heat shock protein expression in human endometrium and steroid-responsive cell lines." European Journal of Endocrinology 133, no. 5 (November 1995): 598–605. http://dx.doi.org/10.1530/eje.0.1330598.
Full textAbstract:
Tang P-Z, Gannon MJ, Andrew A, Miller D. Evidence for oestrogenic regulation of heat shock protein expression in human endometrium and steroid-responsive cell lines. Eur J Endocrinol 1995;133:598–605. ISSN 0804–4643 Gene amplification with target-specific primers (reverse-transcription polymerase chain reaction (RTPCR)) was used to monitor the relative expression of oestrogen and progesterone receptor mRNAs alongside the mRNAs for heat shock proteins HSP 90α, HSP 90β and HSP 70a in normal samples of human endometrial tissue over the whole menstrual cycle and in short-term cultures of steroidresponsive (T47-D) and unresponsive (HRT-18) cell lines exposed to oestradiol and progesterone over a 24-h incubation period. In endometrium, oestrogen and progesterone receptors followed the expected patterns of expression at the protein level during the menstrual cycle and also showed a positive correlation of expression with each other throughout (r = 0.514). Of the HSPs only HSP 90α expression correlated positively with oestrogen receptor (r = 0.687), while HSP 70a expression, which peaked in the late secretory stage, displayed a significantly inverse correlation with HSP 90β expression (r = −0.526). All p values < 0.05. In T47-D cell cultures, oestrogen receptor expression was stimulated transiently by oestradiol (10−7 mol/l) and more persistently by progesterone (10−7 mol/l). Progesterone receptor expression was depressed by progesterone and weakly stimulated by oestradiol. HSP 70a and HSP 90α expression were stimulated by oestradiol. Progesterone generally depressed HSP 90α expression and simultaneous addition of both oestradiol and progesterone to the culture medium was antagonistic to HSP 90α expression. No clear effect of agonist addition on HSP mRNA expression was apparent in the HRT-18 cultures. A possible mechanism for observed oestrogenic effects on HSP expression is put forward. David Miller, Institute of Pathology, Department of Clinical Medicine, Algernon Firth Building, University of Leeds, Leeds, LS2 9JT UK
23
Camacho-Arroyo, I., ST Mendez-Cruz, C. Guerra-Araiza, and MA Cerbon. "Changes in progesterone receptor mRNA content in the rabbit lung during early pregnancy and after sex steroid hormone treatment." Journal of Endocrinology 157, no. 1 (April 1, 1998): 71–74. http://dx.doi.org/10.1677/joe.0.1570071.
Full textAbstract:
In this work we determined progesterone receptor (PR) mRNA content in female rabbit lung during the first 5 days of pregnancy and in ovariectomized animals after subcutaneous injection of oestradiol benzoate (25 micrograms/kg) for 2 days or oestradiol benzoate (25 micrograms/kg) for 2 days plus a single dose of progesterone (5 mg/kg) on day three. On each day (0-5) of pregnancy and 24 h after the last dose in the case of the treated animals, animals were killed and lung was excised; total RNA was extracted and processed for Northern blot analysis. The results showed three main PR mRNA transcripts (6.1, 4.4 and 1.8 kb) in rabbit lung. The 4.4 kb species was the most abundant. PR mRNA content was markedly increased by oestradiol benzoate and downregulated by progesterone. It significantly increased on the first day of pregnancy and then diminished progressively, reaching its lowest value on day 5. These findings suggest that PR mRNA content in the rabbit lung is regulated by sex steroid hormones and changes according to the physiological concentrations of oestradiol and progesterone.
24
Abbot, S. D., K. Docherty, and R. N. Clayton. "Regulation of LH subunit mRNA levels by gonadal hormones in female rats." Journal of Molecular Endocrinology 1, no. 1 (July 1988): 49–60. http://dx.doi.org/10.1677/jme.0.0010049.
Full textAbstract:
ABSTRACT To determine the physiological role of the ovaries in regulation of LH subunit gene expression, levels of cytoplasmic mRNA were measured in a cDNA-RNA dot-blot hybridization assay. An increase (twofold) in α mRNA was first detected 8 days after ovariectomy and then remained stable for 4 weeks. In contrast, LH-β mRNA increased by 60–79% within 12 h of removing the ovaries and then rose progressively to six times the intact values at 3 and 4 weeks. Increases in LH-β mRNA were always greater than those of α mRNA. Oestradiol, and oestradiol plus progesterone, but not progesterone alone, prevented the rise in α and LH-β mRNA 10 days after ovariectomy. Three days after ovariectomy, α mRNA, but not LH-β mRNA, was suppressed to below intact control values by oestradiol and oestradiol plus progesterone, indicating greater sensitivity of α mRNA to oestradiol inhibition at this stage. A single injection of oestradiol (1 μg s.c.) to rats ovariectomized 14 days previously transiently suppressed α and LH-β mRNA levels and serum LH concentrations in parallel for 1–8 h, after which high preinjection values were restored. However, pituitary LH content remained suppressed after LH mRNA levels had returned to the control values of ovariectomized rats. In most instances there was a qualitative positive correlation between changes in α and LH-β mRNA, pituitary LH content and serum LH concentrations. LH content reflected LH-β mRNA changes more closely than those of α mRNA. However, in oestradiol-treated rats ovariectomized 10 days previously, LH content remained increased despite normalization of the LH-β and α mRNA levels, suggesting differential sensitivity to oestradiol of the gene expression and translational processes. Thus divergence of pre- and post-translational regulation of LH biosynthesis was demonstrated. These results imply an important physiological role for female sex hormones in the control of LH gene expression and LH biosynthesis. Prolactin mRNA fell by 30–50% for the first 2 weeks after ovariectomy, but by 3 and 4 weeks values were similar to those of intact controls. Serum and pituitary prolactin levels were reduced by 50% or more at all time-points, despite normalization of mRNA. Treatment of ovariectomized rats for 10 days with oestradiol and progesterone, either alone or combined, reversed the fall in prolactin mRNA and serum and pituitary prolactin levels. These changes in prolactin gene expression and synthesis were opposite to those of LH subunits in response to the same in-vivo hormone manipulations. Growth hormone mRNA levels were unchanged by ovariectomy, oestradiol or progesterone treatment. Levels of TSH-β mRNA increased slightly (maximum up to 50%) after ovariectomy, but were unaltered by oestradiol and progesterone treatment for 10 days. These results support the view that α mRNA changes, resulting from ovariectomy, oestradiol and progesterone treatment, occur in gonadotrophs and not thyrotrophs, which also express the α subunit gene.
25
Sumida, C., C. Gelly, and J. R. Pasqualini. "Dynamics and control of progesterone receptor synthesis in the fetal uterus of the guinea-pig in organ culture." Journal of Endocrinology 105, no. 3 (June 1985): 415–21. http://dx.doi.org/10.1677/joe.0.1050415.
Full textAbstract:
ABSTRACT Progesterone receptor concentrations increased in fetal guinea-pig uterus in organ culture to as high as 13·15±1·22 pmol/mg DNA without any added steroid, although cytosol and nuclear oestrogen receptor levels were very low (0·41−1·92 pmol/mg DNA). Even after a 3-day exposure to 5×10−8 m-progesterone, which inhibits its own receptor (1·14±0·31 pmol/mg DNA), progesterone receptor levels rose to 8·58±1·39 pmol/mg DNA when progesterone was removed. This replenishment was inhibited by progesterone and 5α-dihydroprogesterone but was not affected by oestradiol, tamoxifen or dexamethasone. The incorporation of [3H]thymidine into nucleic acids was not decreased by progesterone so that its inhibition of its own receptor in the explants was not due to an inhibition of cell replication. Fetal uterine explants from oestrogen-primed fetuses, after an initial decrease in progesterone receptor, also showed a rise to 7 pmol/mg DNA on day 2 which could be decreased by exposure to progesterone and replenished by removal of this hormone (6–8 pmol/mg DNA), the entire process occurring without apparent oestrogen stimulation. Progesterone rather than oestradiol appears to be a key regulator of progesterone receptor synthesis in the fetal guinea-pig uterus, although oestradiol, along with other factors, may also be involved. J. Endocr. (1985) 105,415–421
26
Curlewis, JD, and GM Stone. "Effects of Oestradiol, the Oestrous Cycle and Pregnancy on Weight, Metabolism and Cytosol Receptors in the Oviduct and Vaginal Complex of the Brushtail Possum (Trichosurus vulpecula)." Australian Journal of Biological Sciences 40, no. 3 (1987): 315. http://dx.doi.org/10.1071/bi9870315.
Full textAbstract:
Weight, RNA, DNA and protein content of the oviduct, vaginal cul-de-sac, lateral vagina and urogenital sinus and oestradiol and progesterone cytosol receptor concentrations in vaginal cul-de-sac, lateral vagina and urogenital sinus were examined after administration of oestradiol to ovariectomized animals and on days 0, 5, 9 and 13 of the non-pregnant cycle and on day 13 of the pregnant cycle. In ovariectomized animals, oestradiol induced an increase in weight, RNA: DNA and protein: DNA ratios and a decrease in DNA: tissue weight ratio for each organ and in addition an increase in total DNA in vaginal cul-de-sac and urogenital sinus. There was no effect of oestradiol on oestradiol cytosol receptor concentration but there was a significant increase in progesterone cytosol receptor concentration in all organs that were examined.
27
Wathes, D. C., and M. Hamon. "Localization of oestradiol, progesterone and oxytocin receptors in the uterus during the oestrous cycle and early pregnancy of the ewe." Journal of Endocrinology 138, no. 3 (September 1993): 479—NP. http://dx.doi.org/10.1677/joe.0.1380479.
Full textAbstract:
ABSTRACT Uterine tissue samples were collected from 47 ewes at various stages of the oestrous cycle and early pregnancy (until day 21) and during seasonal anoestrus. Cryostat sections were immunostained to determine the localization of oestradiol and progesterone receptors using specific monoclonal antibodies. Oxytocin receptors were localized by autoradiography in sections from the same ewes using the 125I-labelled oxytocin antagonist d(CH2)5[Tyr(Me)2,Thr4,Tyr-NH29]- vasotocin. Plasma progesterone measurements were made during the preceding cycle up to the time of slaughter. Oestradiol receptor concentrations were maximal in all regions of the tract at oestrus. Immunostaining of the luminal epithelium, superficial glandular epithelium, stroma and myometrium decreased in the early luteal phase but was maintained for longer in the deep glands. Progesterone receptor immunostaining in the luminal epithelium and superficial glands developed in the early luteal phase (days 1–2) with a somewhat later appearance in the deep glands (days 5–7). Progesterone receptor concentrations in the stroma and myometrium also reached a maximum in the early luteal phase. Myometrial staining was clearly maintained throughout the luteal phase whereas stromal staining was variable between ewes. For both oestradiol and progesterone receptors no differences were apparent between pregnant and non-pregnant ewes between days 2 and 12, but pregnant ewes did not show the general increases in oestradiol receptor staining associated with luteolysis on days 14–15. Oxytocin receptors first developed in the luminal epithelium of non-pregnant ewes on day 14 of the cycle and spread to the superficial glands, caruncular stroma, deep glands and myometrium at oestrus before decreasing in reverse order on days 1–2. Specific binding was not detectable on days 5–12 of the cycle or on days 14 or 21 of pregnancy. The appearance of oxytocin receptors in the luminal epithelium on day 14 preceded that of both the oestradiol and progesterone receptors in the epithelial cells and the fall in plasma progesterone. It was followed by the development of oestradiol and oxytocin receptors in the superficial glands, deep glands, caruncular stroma and myometrium, with the two receptor populations showing a significant positive association in these tissues. The loss of oxytocin receptors in all regions occurred as plasma progesterone levels were increasing, but the association between these two variables was only significant in the superficial glands. The development of progesterone receptors in different tissues could not be explained on the basis of either oestradiol receptor content or plasma progesterone. We conclude that all three receptor populations change in a dynamic manner during the oestrous cycle with variations both between days and between different uterine compartments. The complex pattern of receptor formation and loss suggests that, in addition to the circulating steroid hormone concentrations, local paracrine factors are likely to be involved in their regulation. Journal of Endocrinology (1993) 138, 479–491
28
Bailey, C. J., J. M. Conlon, and P. R. Flatt. "Effect of ovarian hormones, pregnancy and lactation on somatostatin and substance P in the alimentary tract of mice." Journal of Endocrinology 122, no. 3 (September 1989): 645–50. http://dx.doi.org/10.1677/joe.0.1220645.
Full textAbstract:
ABSTRACT Immunoreactive somatostatin and substance P were determined in extracts of alimentary tract (stomach to colon) from the following groups of adult female mice: intact control, ovariectomized, ovariectomized and treated with oestradiol (50 μg/kg per day) and/or progesterone (2 mg/kg per day) for 30 days, 19-day-pregnant, and 10-day-postpartum lactating. Ovariectomy increased the somatostatin concentration of the stomach (by 52%, P < 0·05), jejunum (by 116%, P < 0·01) and caecum (by 114%, P < 0·01). These effects were partially or totally prevented by the oestradiol and progesterone treatments, especially the oestradiol-progesterone combination, except for an increase (by 126%, P < 0·01) in gastric somatostatin after treatment with oestradiol alone. Lactation also increased gastric somatostatin (by 108%, P < 0·001), but the somatostatin concentration of other regions of the alimentary tract (jejunum to colon) was reduced (by 21–55%, P < 0·05) in pregnant and lactating mice. The concentration of substance P was increased by ovariectomy in stomach (by 69%, P < 0·01), duodenum (by 84%, P < 0·05), ileum (by 163%, P < 0·001) and caecum (by 57%, P < 0·01). This effect was partially or totally prevented by treatment with progesterone alone and by the oestradiol-progesterone combination, but not by oestradiol alone. Pregnancy and lactation increased gastric substance P by 46% (P < 0·01) and 61% (P < 0·001) respectively, but substance P concentrations in other regions of the alimentary tract were not significantly altered. The results suggest that ovarian oestrogens and progestogens are important in the maintenance of normal concentrations of somatostatin and substance P in the gastrointestinal tract of female mice. Journal of Endocrinology (1989) 122, 645–650
29
Bülbül, B., M. Kırbaş, Ş. Dursun, and M. Köse. "Superovulation in cows synchronized with two different progesterone+oestradiol protocols." Archives Animal Breeding 56, no. 1 (October 10, 2013): 160–68. http://dx.doi.org/10.7482/0003-9438-56-015.
Full textAbstract:
Abstract. A total of 26 Brown Swiss cows were used to compare the synchronization and superovulatory response of follicle stimulating hormone treated cows that were synchronized with progesterone+oestradiol valerate or benzoate. Control cows (n = 8) were superstimulated with follicle stimulating hormone using twice daily injections with decreasing doses from day 10–13 after determined reference oestrus. Cows in treatment groups were received either ear implant (n = 9) containing norgestomet+oestradiol valerate or progesterone releasing intravaginal device (n = 9) containing progesterone+oestradiol benzoate, at random stage of the oestrus cycle, for 9 days. Seven days after the implant and progesterone releasing intravaginal device insertion, follicle stimulating hormone was injected as described in the control group. There was no significant difference between the groups for superovulation responses. In conclusion, both protocols synchronized the oestrus cycle in follicle stimulating hormone treated cows and, any of the protocols evaluated in this study can be used as a pretreatment for superstimulation started on the seventh day of the implant or progesterone releasing intravaginal device insertion in Brown Swiss cows.
30
Clarke, I. J., J. T. Cummins, M. E. Crowder, and T. M. Nett. "Long-term negative feedback effects of oestrogen and progesterone on the pituitary gland of the long-term ovariectomized ewe." Journal of Endocrinology 120, no. 2 (February 1989): 207–14. http://dx.doi.org/10.1677/joe.0.1200207.
Full textAbstract:
ABSTRACT The effects of long-term treatment with physiological doses of oestradiol or oestradiol plus progesterone on plasma gonadotrophin levels and pituitary content of LH and gonadotrophin-releasing hormone (GnRH) receptors were studied in ovariectomized–hypothalamo-pituitary disconnected ewes given 250 ng pulses of GnRH every 2 h (i.v.). A pilot experiment showed that 3 cm long Silastic implants (s.c.) reduced both LH pulse frequency and pulse amplitude in long-term (> 6 months) ovariectomized ewes. The main experiment was conducted over 3 weeks in ovariectomized–hypothalamo-pituitary disconnected ewes that had received pulsatile GnRH replacement for 1 week after pituitary surgery. Group 1 (n = 5) received GnRH pulses alone throughout the study. Group 2 (n = 6) received oestradiol in week 2 and oestradiol plus progesterone in week 3 and in group 3 (n = 6) the steroid treatments were reversed. Oestradiol reduced (P < 0·05) the mean (± s.e.m.) amplitude of LH in pulses in group 2 (from 8·2 ± 1·6 to 5·0 ± 0·5 μg/l) and group 3 (from 11·6 ± 1·2 to 9·3 ±1·0 μg/l); an additional effect of progesterone was seen in group 2 but not group 3. The amplitudes of the LH pulses did not change in the control ewes. Plasma concentrations of FSH were reduced by approximately 50% by the oestradiol treatments with no additional effects of progesterone. There was no effect of steroidal treatment on pituitary content of LH or pituitary levels of GnRH receptors. We conclude that long-term oestradiol treatment, with or without progesterone, reduces plasma amplitudes of LH pulses by a direct pituitary effect, but the magnitude of this effect was less than that observed on GnRH secretion in short-term ovariectomized ewes in an earlier study. The reduction in plasma LH pulse amplitude is not due to a direct pituitary effect of these steroids on GnRH receptor number. Journal of Endocrinology (1989) 120, 207–214
31
Terazono, T., V. V. Luu, L. T. K. Do, M. Taniguchi, M. Takagi, and T. Otoi. "183 ULTRASONOGRAPHIC MONITORING OF CANINE OVARIES CLAMPED AT SUBCUTANEOUS SITE AFTER FOLLICLE-STIMULATING HORMONE TREATMENT." Reproduction, Fertility and Development 27, no. 1 (2015): 183. http://dx.doi.org/10.1071/rdv27n1ab183.
Full textAbstract:
Follicle-stimulating hormone (FSH) alone can induce oestrus in bitches, but few reports describe oestrous induction by FSH because pregnant mare serum gonadotrophin (PMSG) has been more successful than FSH for oestrus induction. Real-time ultrasonography can show canine ovarian follicle development, but no method can determine or predict ovulation accurately. Moreover, the ovary location and size complicate imaging. Using ultrasonography, we investigated FSH treatment stimulation of canine ovary follicles, with clamping of the ovaries at a subcutaneous site. Bilateral malacotomy of four 5-year-old Beagle bitches (mean weight 10.3 ± 2.0 kg) with normal oestrous cycles was done using a ventral flank abdominal approach with routine techniques and materials. Each ovary that maintained blood circulation from the suspensory ligament was clamped at a subcutaneous site through muscles of the abdomen. After about six months of bilateral malacotomy, four bitches at the anestrous (two bitches) and diestrous (two bitches) stages of the oestrous cycle were given 0.5 Armour units of FSH twice daily for 5 days. Examinations with ovarian ultrasonography with 7.5 MHz sector transducer, vaginal cytology, and serum concentrations of progesterone and oestradiol were performed daily from the day before the start of FSH treatment through 7 days after FSH treatment. After 15 days of ovarian examination, each bitch received the same FSH treatment twice continually at 15-day intervals. No serosanguineous vaginal discharge was observed during the ovarian examination. The concentrations of progesterone (<0.045–9.6 ng mL–1) and oestradiol (<9.7–81.4 pg mL–1) varied through all treatments. Comparison of the concentrations of progesterone (<0.045–7.6 ng mL–1) and oestradiol (<9.7–30.3 pg mL–1) at the start of FSH administration in each trial revealed that elevated concentrations of both progesterone and oestradiol were observed in the first treatment in 3 bitches. Regarding the second and third treatments, no elevation of concentration was found for progesterone or oestradiol. A new follicular growth was observed in 1 animal after the third FSH treatment, but no follicular growth was found for the other animals. No correlation was found between follicular development and the profile of either progesterone or oestradiol. Ultrasonography proved that FSH stimulation alone cannot induce follicular growth by a single treatment, but it might increase the levels of progesterone and oestradiol, which are not correlated with follicular development and oestrous cycles at the start of FSH treatment.
32
Aurich, C., P. F. Daels, B. A. Ball, and J. E. Aurich. "Effects of gonadal steroids on the opioid regulation of LH and prolactin release in ovariectomized pony mares." Journal of Endocrinology 147, no. 2 (November 1995): 195–202. http://dx.doi.org/10.1677/joe.0.1470195.
Full textAbstract:
Abstract The aim of the present study was to investigate the role of ovarian steroids in the opioid regulation of LH and prolactin release in mares. Effects of the opioid antagonist naloxone on LH and prolactin secretion were determined in ovariectomized pony mares. The animals were pretreated with either progesterone (500 μg kg−1) or oestradiol benzoate (10 μg kg−1) for 8 days and subsequently with a combination of progesterone and oestradiol for an additional 8 days. Naloxone administration (0·5 mg kg−1 i.v.) resulted in a significant release of LH as well as prolactin in mares after pretreatment with either oestradiol benzoate or progesterone plus oestradiol benzoate (P<0·05). No significant changes in LH and prolactin secretion were detected in progesterone-treated and non-steroid-treated ovariectomized mares. These results indicate that a prolonged oestrogen influence activates the opioid inhibition of LH and prolactin release in mares. In contrast to other species, progesterone alone does not activate a tonic opioid inhibition of LH and prolactin secretion, but modulates the effect of oestrogens. The opioid systems therefore seem to be regulated by a sequence of different steroid environments, as found during the oestrous cycle. The parallel increases in prolactin and LH secretion in mares may indicate a common regulatory pathway for these two hormones. Journal of Endocrinology (1995) 147, 195–202
33
Glencross, R. G. "Effect of pulsatile infusion of gonadotrophin-releasing hormone on plasma oestradiol-17β concentrations and follicular development during naturally and artificially maintained high levels of plasma progesterone in heifers." Journal of Endocrinology 112, no. 1 (January 1987): 77–85. http://dx.doi.org/10.1677/joe.0.1120077.
Full textAbstract:
ABSTRACT To stimulate a follicular-phase pattern of pulsatile LH release, gonadotrophin-releasing hormone (GnRH; 5 μg) was infused (i.v.) hourly into heifers for periods of 5–11 days during the luteal phase of the oestrous cycle, and also when plasma progesterone levels were increased artificially by means of a progesterone-releasing intravaginal device. Plasma oestradiol-17β concentrations increased from basal (EEE 2·5 pmol/l) to preovulatory peak levels (20–30 pmol/l) during the first 3 days of GnRH treatment. They were maintained at these values before returning to basal levels within 24 h of cessation of infusion. This response occurred regardless of the source of progesterone (endogenous or administered). Follicular development was observed by ovarian palpation (per rectum) in some heifers at the time of maximum secretion of oestradiol-17β. There was no detectable cervical mucus secretion or oestrous behaviour during these periods of high oestradiol-17β levels and ovulation did not occur. Treatment with GnRH did not affect plasma progesterone concentrations or oestrous cycle length. The study shows that oestradiol-17β secretion and follicular development (and the accompanying oestrus and ovulation) are suppressed during the luteal phase of the cycle by high concentrations of plasma progesterone, and provides strong indirect evidence that such inhibition is associated with a reduction in the pulse frequency of LH release. J. Endocr. (1987) 112, 77–85
34
Byrne, B., P. A. Fowler, and A. Templeton. "The effects of steroidal and non-steroidal ovarian hormones on pituitary responsiveness to gonadotrophin surge-attenuating factor." Journal of Endocrinology 150, no. 3 (September 1996): 413–22. http://dx.doi.org/10.1677/joe.0.1500413.
Full textAbstract:
Abstract Primary pituitary cultures from adult female rats were used to investigate the effects of steroidal (oestradiol and progesterone) and non-steroidal (inhibin, follistatin) ovarian hormones on the suppressive actions of the ovarian factor gonadotrophin surge-attenuating factor (GnSAF) in the control of gonadotrophin secretion. The source of GnSAF was a chromatographic preparation from follicular fluid containing four distinct protein bands as resolved on SDS–PAGE. Oestradiol and progesterone added alone had no effect on gonadotrophin secretion but had a wide range of effects on the suppression of both LH and FSH secretion caused by the non-steroidal factors. Oestradiol, progesterone and oestradiol+progesterone enhanced the suppressive actions of GnSAF on GnRH-induced LH secretion (causing 19·3 ± 5·2% (P<0·05), 41·9 ± 3·4% (P<0·001) and 32·2 ± 5·3% (P<0·001) greater suppression than GnSAF alone). Progesterone and oestradiol+progesterone completely abolished the suppression of basal FSH secretion caused by inhibin (causing 157·1 ± 22·2%, P<0·001, and 160·9 ± 11·3%, P<0·001, stimulation compared with inhibin alone). Separately the steroids had no effect on the suppression of gonadotrophin secretion caused by follistatin. However, in combination, oestradiol+ progesterone potentiated the suppressive actions of follistatin on GnRH-induced LH secretion causing 29·9 ± 5·3% (P<0·05) greater suppression than follistatin alone. In combination, high-dose follistatin and GnSAF caused 31·1 ±6·5% (P<0·01) greater suppression than GnSAF alone. Thus in combination high-dose follistatin and GnSAF have additive effects on the suppression of GnRH-induced LH secretion. Recombinant human inhibin and GnSAF added in combination had little further effect compared with either alone suggesting that they may have a similar mechanism of action at the pituitary level. These results demonstrate that while FSH secretion in vitro is mainly controlled by inhibin and follistatin, LH secretion is affected by the presence of a whole range of factors. We have demonstrated that oestradiol and progesterone potentiate the suppressive actions of GnSAF in vitro. These data are compatible with the suggestion that in the late follicular phase it is falling levels of GnSAF that allow positive feedback of the steroids on the pituitary to elicit the LH surge, rather than increases in the stimulatory effects of the ovarian steroids overcoming GnSAF. The actions of GnSAF on the pituitary may be modulated by follistatin but it is unlikely that inhibin has any modulatory effects on the GnSAF-induced suppression of LH secretion. Journal of Endocrinology (1996) 150, 413–422
35
Hu, Jianbo, Gheorghe T. Braileanu, and Mark A. Mirando. "Effect of ovarian steroids on basal and oxytocin-induced prostaglandin F2α secretion from pig endometrial cells." Reproduction, Fertility and Development 15, no. 4 (2003): 197. http://dx.doi.org/10.1071/rd03024.
Full textAbstract:
These studies were undertaken to determine how treatment with 100 nM progesterone and/or 10 nM oestradiol-17β acutely (3 h; Experiment 1) or chronically (72 h; Experiments 2–4) influenced basal and oxytocin (OT)-stimulated prostaglandin (PG) F2α secretion, in enriched cultures of pig endometrial luminal epithelial, glandular epithelial and stromal cells obtained on Day 16 (Experiments 1, 2 and 4) or Day 12 (Experiment 3) after oestrus. In Experiment 1, acute treatment with progesterone stimulated PGF2α secretion from each cell type on Day 16, whereas acute oestradiol treatment inhibited the stimulatory action of progesterone on PGF2α secretion only in glandular epithelial cells. In Experiment 2, OT stimulated phospholipase (PL) C activity in luminal epithelial cells on Day 16 only in the presence of chronic oestradiol treatment. For glandular epithelial cells on Day 16, OT stimulated PLC activity only in the presence of chronic treatment with steroid. In stromal cells on Day 16, OT stimulated PLC activity in the absence of steroids and the response to OT was further enhanced by oestradiol. In the absence of chronic treatment with steroid, OT did not stimulate PGF2α secretion from luminal epithelial cells, but oestradiol induced a response to OT. For glandular epithelial cells, OT-induced PGF2α secretion was not altered by steroids, whereas the stimulatory response to OT was inhibited by oestradiol or progesterone in stromal cells. For endometrial cells obtained on Day 12 after oestrus in Experiment 3, OT only stimulated PGF2α release from glandular epithelial and stromal cells. For luminal epithelial cells obtained on Day 16 after oestrus and cultured under polarizing conditions in Experiment 4, secretion of PGF2α occurred preferentially from the basolateral surface and was stimulated by OT more from the basolateral surface than from the apical surface. Oxytocin-induced PGF2α secretion from the apical surface was enhanced by chronic treatment with oestradiol, whereas that from the basolateral surface was enhanced by chronic treatment with progesterone. In summary, oestradiol enhanced OT-induced PGF2α secretion from the apical surface of luminal epithelial cells and reduced the response of stromal cells to OT, actions that may contribute to the reorientation of PGF2α from endocrine secretion (i.e. towards the uterine vasculature) to exocrine secretion (i.e. towards the uterine lumen) during pregnancy recognition in pigs.
36
ELLIOTT, K. J., N. T. CABLE, T. REILLY, and M. J. DIVER. "Effect of menstrual cycle phase on the concentration of bioavailable 17-β oestradiol and testosterone and muscle strength." Clinical Science 105, no. 6 (December 1, 2003): 663–69. http://dx.doi.org/10.1042/cs20020360.
Full textAbstract:
To investigate the effect of changes in sex hormone concentration on muscle strength and the bioavailability of 17-β oestradiol (oestradiol) and testosterone, seven eumenorrheic females were tested during two phases of the menstrual cycle. Maximum voluntary isometric strength of the first dorsal interosseus muscle was measured during the early follicular and mid-luteal phases of the menstrual cycle. These phases were chosen for testing as the concentration of total oestradiol is significantly different in these two phases. Total oestradiol has been repeatedly associated with changes in muscle strength in females, whereas the effects of bioavailable oestradiol are unknown. The concentrations of total and bioavailable oestradiol and testosterone were measured in addition to the concentration of total progesterone. Concentrations of total progesterone and oestradiol were significantly different between the early follicular and mid-luteal phases of the menstrual cycle (P<0.05 and P<0.001 respectively). The concentration of total testosterone (0.7±0.2 and 0.8±0.1 nmol·l-1 respectively) and the ratio of total oestradiol to progesterone (153.0±251.2 and 108.5±27.8 respectively) did not change significantly between the early follicular and mid-luteal phases. Bioavailable testosterone (102.2±66.3 and 105.0±90.2 pmol·l-1 respectively) and bioavailable oestradiol (90.5±35.5 and 120.0±60.6 pmol·l-1 respectively) did not differ significantly between phases. There were no significant differences in muscle strength during the menstrual cycle (P=0.1). Mean maximum voluntary isometric force of the first dorsal interosseus muscle did not correlate significantly with the mean concentration of any reproductive hormone measured. These results indicate that cyclical variation in endogenous reproductive hormones does not affect muscle strength.
37
Woodward, T. L., W. E. Beal, and R. M. Akers. "Cell interactions in initiation of mammary epithelial proliferation by oestradiol and progesterone in prepubertal heifers." Journal of Endocrinology 136, no. 1 (January 1993): 149–57. http://dx.doi.org/10.1677/joe.0.1360149.
Full textAbstract:
ABSTRACT The acute temporal effects of exogenous oestradiol (0·1 mg/kg per day), progesterone (0·25 mg/kg per day) or both together on the proliferative response of epithelial cells, fibroblasts, adipocytes and endothelial cells in the mammary tissue of prepubertal cross-bred heifers were determined. Mammary biopsies were taken immediately before, then 24, 48 and 96 h after the initiation of daily administration of hormones to three heifers per treatment group. Incorporation of [3H]thymidine into explants prepared from biopsies was evaluated after a 1-h incubation by measuring trichloroacetic acid (TCA)-insoluble radioactivity in explant homogenates as well as by quantitative histoautoradiography. Incorporation expressed as d.p.m./mg tissue or d.p.m./μg DNA was increased (P ≤ 0·05) approximately 11-fold by 96 h in oestradiol-treated heifers. Progesterone-treated animals were unresponsive and heifers treated with both hormones were intermediate in response compared with oestradiol-treated heifers. Autoradiographic data for ductal or terminal duct epithelial cells showed similar dramatic increases in labelling by 24 h with further increased (P < 0·01) labelling by 96 h (5·1% vs 0·1%) in heifers given oestradiol. As with incorporation, tissue from progesterone-treated heifers showed no time or treatment response compared with pretreatment biopsies and tissue from heifers given both showed intermediate responses, i.e. significantly increased labelling by 96 h compared with pretreatment (P ≤ 0·05) but less labelling (P < 0·05) than oestradiol-treated heifers. A proliferative response of epithelial cells in oestradiol-treated heifers occurred prior to the response of fibroblasts adjacent to epithelial cells (≤ 50 μm). Interestingly, labelling of endothelial cells was also markedly increased by 48 h in oestradiol-treated heifers. Non-adjacent fibroblasts (≥ 100 μm from ductal epithelial cells) and adipocytes showed no time or treatment response. These data demonstrate that exogenous oestradiol markedly and acutely stimulates proliferation of mammary ducts, while progesterone has no effect and may decrease the effectiveness of oestradiol. In contrast to mice, mammary epithelial response to oestradiol in prepubertal heifers is not first exhibited after a proliferative response of stromal cells. This suggests that the cell-type interactions involved in the control of mammogenesis are dissimilar in ruminants and rodents. Journal of Endocrinology (1993) 136, 149–157
38
Sheldrick, EL. "Oxytocin delays oestradiol-induced luteolysis but does not affect oestradiol-induced luteinizing hormone secretion in the ewe." Reproduction, Fertility and Development 4, no. 5 (1992): 593. http://dx.doi.org/10.1071/rd9920593.
Full textAbstract:
Circulating concentrations of progesterone, the prostaglandin F2 alpha (PGF2 alpha), metabolite 13,14-dihydro-15-keto PGF2 alpha (DHKF2 alpha) and luteinizing hormone (LH) have been measured in cyclic ewes receiving a continuous infusion of oxytocin, in order to investigate the effect of maintained concentrations of circulating oxytocin on the luteolytic action of oestradiol-17 beta. Oxytocin (3 nmol h-1 intravenously) was given from Day 7 until Day 17 after oestrus with oestradiol-17 beta (2.76 mumol, intramuscularly in sesame oil, 0.5 mL-1) administered on Days 9 and 10. Control ewes, given a continuous infusion of saline (154 mmol L-1, 3 mL-1 h-1) and sesame oil on Days 9 and 10, underwent luteal regression at the expected time, with mean concentrations of plasma progesterone falling to below 1.5 nmol L-1 on Day 16 (0900 hours). Mean plasma progesterone concentrations fell to less than 1.5 nmol L-1 on Day 13 (0900 hours) in ewes receiving saline and oestradiol-17 beta. Oxytocin infusion delayed luteolysis in all treated ewes; those receiving oxytocin infusion and sesame oil failed to undergo luteal regression during the period studied and in animals receiving oxytocin and oestradiol-17 beta, luteolysis was significantly delayed when compared to ewes treated with saline and oestradiol with progesterone concentrations falling to < 1.5 nmol L-1 on Days 14 (n = 1 ewe), 15 (n = 1 ewe), 16 (n = 2 ewes) and > 17 (n = 2 ewes) (P < 0.05).
39
Mittal, M., N. Panay, PR Supramaniam, M. Savvas, L. Cardozo, and H. Hamoda. "A direct comparison of women’s perceptions and acceptability of micronised progesterone and medroxyprogesterone acetate in combination with transdermal oestradiol in the management of young postmenopausal women, under 45 years of age." Post Reproductive Health 26, no. 4 (October 12, 2020): 210–19. http://dx.doi.org/10.1177/2053369120960960.
Full textAbstract:
Objective To assess the acceptability and perception of postmenopausal women, to two different hormone replacement therapy regimens, in relation to the control of their symptoms and development of adverse effects. Study design Prospectively recruited postmenopausal women, <45 years, were randomised to one of two treatment arms for 12-months: cyclical micronised progesterone or medroxyprogesterone acetate in combination with transdermal oestradiol. A self-reported questionnaire with matrix rating scales was completed and repeated after 3, 6 and 12-months. Main outcome measures Symptom control and development of adverse effects. Results Seventy-one individuals were screened, with baseline data available for 67 subjects. A total of 190 questionnaires were returned. The most commonly reported symptoms were low energy levels, vasomotor symptoms and sexual dysfunction. The prevalence of adverse effects ranged between 57.89 and 87.50%, with a reduction seen in the transdermal oestradiol + micronised progesterone arm (73.91% at 3-months, decreasing to 57.89% at 12-months; p = 0.33), compared to the transdermal oestradiol + medroxyprogesterone acetate arm (76.92% at 3-months, increasing to 87.50% at 12-months; p = 0.69). The main reported adverse effects were bloating, weight change and psychological symptoms. A significant difference was documented between the groups after set intervals, with a greater proportion reporting breast tenderness after 3-months (p = 0.01), lower numbers reporting mood swings at 6-months (p = 0.01) and irritability at 12-months (p = 0.03) in the transdermal oestradiol + micronised progesterone arm compared to the transdermal oestradiol + medroxyprogesterone acetate arm. Conclusions The acceptability of both regimens was high despite adverse effects, but tolerability of transdermal oestradiol combined with micronised progesterone appeared to be better with fewer women reporting psychological concerns.
40
Mann, G. E., B. K. Campbell, A. S. McNeilly, and D. T. Baird. "The role of inhibin and oestradiol in the control of FSH secretion in the sheep." Journal of Endocrinology 133, no. 3 (June 1992): 381–91. http://dx.doi.org/10.1677/joe.0.1330381.
Full textAbstract:
ABSTRACT The relative importance of inhibin and oestradiol in the control of FSH and LH secretion in the ewe was investigated by passive immunization in intact animals and by hormone replacement therapy following acute ovariectomy, in the same experiment. Mature Scottish Blackface ewes on day 10 of the luteal phase were allocated to nine groups of four to five animals. Four groups were ovariectomized and immediately treated with either progesterone alone or in combination with steroid-stripped ovine follicular fluid ('inhibin') and/or oestradiol. Three further groups of ewes were left intact and injected with antibodies to the 1–26α peptide fragment of porcine inhibin and/or oestradiol-17β. Two groups of animals were either ovariectomized alone with no further treatment, or were left intact and treated with normal sheep plasma to act as controls. Blood samples were collected at 2 h intervals from 12 h before until 48 h after ovariectomy/immunization, and from 12 to 24 h after treatment, blood samples were collected at 10-min intervals. After ovariectomy there was a large rise in the peripheral concentration of LH (P < 0·001) which was not affected by treatment with progesterone alone but was completely prevented by treatment with progesterone and oestradiol. Treatment with inhibin had no effect on this post-castrational rise in LH. In intact ewes, immunization against oestradiol, alone or in combination with inhibin, resulted in a rise in the concentration of LH, while immunization against inhibin had no effect on LH concentration. The peripheral concentration of FSH showed a significant (P < 0·001) increase after ovariectomy which was not affected by treatment with progesterone alone. Treatment with inhibin or oestradiol alone caused a significant (P < 0·01) reduction in this rise, while treatment with inhibin and oestradiol together completely prevented this post-castrational rise in FSH concentration. Passive immunization against inhibin or oestradiol alone resulted in a transitory (P< 0·01) rise in the peripheral concentration of FSH, while immunization against the two hormones in combination resulted in a significantly (P < 0·01) larger rise. During the 14-h period after treatment, the rise in the concentration of FSH in this combined immunization group was not significantly different from that seen in the control ovariectomized group. These results provide evidence that FSH secretion is under the control of both oestradiol and inhibin, while reinforcing the hypothesis that inhibin is not involved in the regulation of LH production, which is under the dual control of oestradiol and progesterone. Journal of Endocrinology (1992) 133, 381–391
41
Paulsson, Bodil, Thomas Gredmark, Pawel Burian, and Mats Bende. "Nasal mucosal congestion during the menstrual cycle." Journal of Laryngology & Otology 111, no. 4 (April 1997): 337–39. http://dx.doi.org/10.1017/s0022215100137259.
Full textAbstract:
AbstractA relationship between the reactivity of the nasal mucosa and changes in female sex hormones have been debated for a long time, although no evidence has been presented to prove or disprove this relationship. Nasal patency was therefore measured by nasal expiratory peak-flow in 26 women for two months in order to study changes in nasal mucosal congestion during the menstrual cycle. In another eight women, nasal congestion was measured by acoustic rhinometry, and symptoms of nasal stuffiness were registered during periods when there were various levels of plasma oestradiol and progesterone. Finally, nasal mucosal biopsies were taken for preparation of receptors for oestradiol and progesterone. This study could not verify the effects of female sex hormones on the nasal mucosa. This could be explained by the fact that no receptors for oestradiol and progesterone were found.
42
Lin, C. L., and H. L. Buttle. "Effect of oestradiol benzoate and tamoxifen on the growth of and induction of progesterone receptors in the uterus and mammary gland of immature pigs." Journal of Endocrinology 130, no. 2 (August 1991): 259–65. http://dx.doi.org/10.1677/joe.0.1300259.
Full textAbstract:
ABSTRACT Intramuscular injection of oestradiol benzoate (0·1, 1 or 10 μg/kg per day) and tamoxifen (0·1 or 1 mg/kg per day) to 6-week-old immature pigs for 7 days induced a dose-dependent increase in the wet weight of the uterus and in the total content of uterine DNA, RNA and protein. Both compounds also stimulated a dose-dependent increase in the concentration of progesterone receptors in uterine cytosolic extracts (in terms of either fmol/mg DNA or fmol/g uterus). The concurrent administration of tamoxifen with oestradiol benzoate provoked significant (P < 0·05) increases in total uterine protein and in the concentration of progesterone receptors (P < 0·01) compared with treatment with oestradiol benzoate alone. Hence tamoxifen is an oestrogen agonist in the uterus of immature pigs. The effects of oestradiol benzoate and tamoxifen on mammary growth in immature pigs were assessed by image analysis of mammary sections across the gland (in a ventro-dorsal direction through the teat). Oestradiol benzoate at 10 μg/kg per day stimulated a fourfold increase in mammary duct area (P < 0·01), and tamoxifen, at doses of 0·1 or 1 mg/kg per day, stimulated a threefold increase (P < 0·05). Tamoxifen partially inhibited (P < 0·05) the effect of oestradiol benzoate. The concentration of progesterone receptors was found to be very heterogeneous in cytosol extracts of mammary tissue of immature pigs and independent of treatment with oestradiol benzoate and/or tamoxifen. Journal of Endocrinology (1991) 130, 259–265
43
Cagampang, F. R. A., K. I. Maeda, H. Tsukamura, S. Ohkura, and K. Ôta. "Involvement of ovarian steroids and endogenous opioids in the fasting-induced suppression of pulsatile LH release in ovariectomized rats." Journal of Endocrinology 129, no. 3 (June 1991): 321–28. http://dx.doi.org/10.1677/joe.0.1290321.
Full textAbstract:
ABSTRACT The participation of the ovarian steroids and opioid peptides in the suppression of pulsatile LH release during acute fasting was examined in rats. Ovariectomized rats bearing silicone elastomer implants of oestradiol and/or progesterone were fasted for 48 h and subsequently blood samples were taken every 6 min for 3 h. Pulsatile LH release was suppressed after 48 h of fasting in the ovariectomized rats implanted with oestradiol but not in the oil-implanted controls. This suppression was enhanced after the administration of progesterone together with oestradiol. In a second experiment, ovariectomized rats bearing implants of oestradiol or oil were fasted for 48 h and injected s.c. (2·5 mg/kg body weight) with an opioid antagonist, naloxone hydrochloride, immediately before blood sampling. In the fasted oestradiol-treated ovariectomized rats, naloxone was able to prevent the suppression of pulsatile LH release. In the absence of oestradiol, however, naloxone was without effect on LH release in either the fasted or unfasted animals. These experiments indicate that the suppression of pulsatile LH release after 48 h of fasting is dependent upon oestradiol and that endogenous opioids are involved in the suppression. Journal of Endocrinology (1991) 129, 321–328
44
Satué, Katy, Paloma Montesinos, and Ana MuÑoz. "Modulation of the renin–angiotensin–aldosterone system by steroid hormones during the oestrous cycle in mares." Acta Veterinaria Hungarica 68, no. 1 (March 2020): 79–84. http://dx.doi.org/10.1556/004.2020.00011.
Full textAbstract:
AbstractIn women and females of different species of laboratory animals, oestrogens stimulate the renin–angiotensin–aldosterone system (RAAS) by increasing tissue and circulating levels of angiotensinogen and renin during the preovulatory period. Progesterone and cortisol compete with aldosterone for mineralocorticoid receptors, which results in increased Na+ reabsorption during the postovulatory period. The purpose of the current research was to analyse the relationship of oestradiol-17β, progesterone and cortisol with RAAS in 23 mares during an oestrous cycle. During the preovulatory period, significant positive correlations of oestradiol-17β with renin and aldosterone concentrations and negative correlations of progesterone with renin and aldosterone concentrations were found. In contrast, during the postovulatory period, oestradiol-17β concentrations were positively correlated with angiotensin concentrations and progesterone was negatively correlated with this component of the RAAS. Cortisol concentrations were not correlated with the hormones of the RAAS, neither before nor after ovulation. This research demonstrates that, as occurs in other species, changes in the RAAS during the periovulatory period in mares may be modulated by variations in the concentrations of steroid hormones.
45
Yun, Wong Shun, C. S. Ho, N. S. Panesar, and R. Swaminathan. "The Contribution of Steroids to Digoxin-Like Immunoreactivity in Cord Blood." Annals of Clinical Biochemistry: International Journal of Laboratory Medicine 29, no. 3 (May 1992): 337–42. http://dx.doi.org/10.1177/000456329202900315.
Full textAbstract:
Samples of cord serum from 29 healthy neonates were analysed for digoxin-like immunoreactive substance (DLIS), cortisol, 17β-oestradiol, progesterone, dehydroepiandrosterone-sulphate (DHEAS), 17α-hydroxyprogesterone (17OHP), androstenedione, oestriol and ouabain-like activity (OLA; by inhibition of Na+,K+ ATPase activity). The mean serum concentration of DLIS was 0·91 (SD = 0·19) nmol/L and the mean OLA was 26·1 (SD = 11·5) nmol/L. There was no correlation between DLIS and OLA. DLIS correlated significantly with oestriol ( r = 0·521), progesterone ( r = 0·534) and 17OHP ( r = 0·43). Stepwise multiple regression analysis showed that 17β-oestradiol, progesterone and androstenedione contributed to DLIS and the intercept was 0·64 (SD = 0·127). The concentrations of steroids (17β-oestradiol, progesterone, androstenedione) required to displace digoxin by 50% in the digoxin immunoassay and inhibit Na+,K+ ATPase in the OLA assay were 103–104-fold higher than those found in cord serum. We conclude that the contribution of these steroids to DLIS is small and that DLIS and OLA measure different compounds.
46
Södersten, P., and P. Eneroth. "Dissociation between the ovarian factors controlling sexual receptivity and preovulatory secretion of LH in cyclic female rats." Journal of Endocrinology 112, no. 1 (January 1987): 133–38. http://dx.doi.org/10.1677/joe.0.1120133.
Full textAbstract:
ABSTRACT Ovariectomy and treatment with oestradiol benzoate (10 μg OB) on the day before behavioural oestrus eliminated the preovulatory surge of LH and reduced the level of sexual receptivity on the following day. Sexual behaviour, but not the LH surge, was restored by progesterone (0·5 mg) given 18 h later. Injection of OB on the day after behavioural oestrus induced a small release of LH and normal sexual behaviour on the following day. Ovariectomy on the day after behavioural oestrus reduced the stimulatory effect of OB on sexual behaviour and eliminated its weakly stimulatory effect on LH release. Sexual behaviour, but not the small LH surge, was restored in these animals by progesterone (0·5 mg) given 18 h later. Treatment of rats ovariectomized 2 days before the day of the LH surge with implants containing oestradiol or injections of oestradiol (1 μg) induced LH surges but the amplitudes of these LH surges were much smaller than those of the normal LH surge. Treatment of intact rats with OB increased serum progesterone levels 24 h later, an effect which was eliminated by ovariectomy. Injections of LH (20 μg) into intact rats on the day after behavioural oestrus also increased serum progesterone concentrations but failed to stimulate sexual behaviour. It is suggested that OB treatment of intact rats on the day after behavioural oestrus stimulates sexual behaviour by inducing a surge of LH secretion which activates ovarian secretion of progesterone. Thus, oestrogen and progesterone but not the LH surge are essential for sexual behaviour. Whereas oestradiol and progesterone restore normal sexual behaviour in ovariectomized rats, additional ovarian factors may be required for induction of normal LH surges. J. Endocr. (1987) 112, 133–138
47
Downing, S. J., and M. Hollingsworth. "Influence of ovarian steroids on myometrial sensitivity and tolerance to relaxin in the rat in vivo: lack of cross-tolerance between relaxin, salbutamol and cromakalim." Journal of Endocrinology 135, no. 1 (October 1992): 17–28. http://dx.doi.org/10.1677/joe.0.1350017.
Full textAbstract:
ABSTRACT The influence of oestradiol benzoate and progesterone on uterine sensitivity and development of tolerance to relaxin was investigated in bilaterally ovariectomized non-pregnant rats in vivo. Bolus doses of relaxin (2–20 μg/kg i.v.) produced rapid and reversible inhibition of uterine contractions in a dose-dependent manner. Treatment with oestradiol benzoate or oestradiol benzoate plus progesterone significantly increased uterine sensitivity to relaxin over 48 h by 2·4- to 8·5-fold. Tolerance to relaxin developed during continuous infusion of the hormone at 20 μg/kg per h for 40 h. A 7·8- to 17·4-fold reduction in sensitivity to relaxin was observed in relaxin-infused rats, whereas no change in sensitivity was observed in saline-infused rats. Infusion of relaxin at 50 μg/kg per h for 40 h produced a 131·8-fold reduction in uterine sensitivity to relaxin. The uterus remained tolerant to relaxin for up to 24 h after cessation of infusion. Treatment with oestradiol benzoate and/or progesterone did not influence the extent of tolerance development, but a more rapid recovery of uterine sensitivity to relaxin was observed in rats treated with oestradiol benzoate plus progesterone. Cross-tolerance with other uterine relaxant drugs was measured to investigate possible common mechanisms of action and sites of tolerance between relaxin and a β-adrenoceptor agonist (salbutamol) and potassium channel openers (cromakalim and minoxidil sulphate). No cross-tolerance was observed between relaxin and salbutamol, or relaxin and cromakalim or minoxidil sulphate. Cross-tolerance between cromakalim and minoxidil sulphate was seen. Journal of Endocrinology (1992) 135, 17–28
48
Andersson, Ola, Margareta Blombäck, Katarina Bremme, and Håkan Wramsby. "Prediction of Changes in Levels of Haemostatic Variables during Natural Menstrual Cycle and Ovarian Hyperstimulation." Thrombosis and Haemostasis 77, no. 05 (1997): 0901–4. http://dx.doi.org/10.1055/s-0038-1656075.
Full textAbstract:
SummaryTo find if there is a relation between levels of haemostatic variables at low and high hormonal levels (oestradiol and progesterone) in an individual, blood samples were drawn from 12 women repeatedly during one menstrual cycle (Study I) and from 14 women undergoing in vitro fertilization, before hormonal stimulation and daily during the periovu- latory period (Study II). Regression coefficients were calculated between minimum (independent) and maximum (dependent) values in both studies. In Study II highly significant regression coefficients were found between oestradiol minimum (pretreatment) and maximum (mcdian 105 and 4730 pmol/1, respectively) for coagulation factors FVIII, von Willebrand Factor (antigen), FVII (activity and antigen), fibrinogen, protein C, protein S (free), antithrombin, plasminogen and plasminogen activator inhibitor-1; furthermore, between progesterone-minimum at day -3 or -2 (related to ovum pick up) and maximum (median 4.7 and 98 nmol/1, respectively) for FVIII, von Willebrand Factor, FVII (activity and antigen), protein C, protein S (free), and plasminogen. In Study I, where much lower hormonal levels were obtained at maximum (oestradiol median 297 pmol/1 and and progesterone 47 nmol/1), the same pattern was observed especially for FVIII, FX, fibrinogen, plasminogen and plasmin inhibitor. Thus, the concentration of a haemostatic variable at a low oestradiol or progesterone level can predict the level at a high hormonal level.
49
David, G. F. X., V. Puri, A. K. Dubey, C. P. Puri, and T. C. Anand Kumar. "Reproductive endocrine effects of intranasal administration of progesterone to adult female rhesus monkeys." Acta Endocrinologica 110, no. 4 (December 1985): 461–68. http://dx.doi.org/10.1530/acta.0.1100461.
Full textAbstract:
Abstract. Adult female rhesus monkeys exhibiting normal ovulatory menstrual cycles were treated with progesterone nasal sprays. Animals in group A (n = 9) were treated with the solvent only (controls). Animals in groups B (n = 6), C (n = 17) and D (n = 7), respectively, were treated with a daily dose of 0.4, 2 and 10 μg of progesterone and the spraying was done between days 5–14 of the cycle. Ovulation was monitored by laparoscopy on day 20. The serum endocrine profile throughout the treated menstrual cycle was studied with respect to oestradiol and progesterone. Bioactive luteinizing hormone (bLH) was studied in blood samples taken on the day of the mid-cycle oestradiol peak, 2 days before, and 2 days after. The menstrual cycle was divided into two phases with respect to the mid-cycle oestradiol peak: phase I was taken to include day 1 of the cycle to the day of the oestradiol peak, and the remaining part of the menstrual cycle was considered to be phase II. The serum-endocrine profile in the controls was similar to that observed in normal ovulatory menstrual cycles. However, in the progesterone-treated groups three types of menstrual cycles were discernable on the basis of the serum endocrine profile. In the type I menstrual cycle, observed only in group C (n = 10), the mid-cycle bLH peak was abolished and the progesterone levels remained low throughout the cycle. Laparoscopy revealed these to be anovulatory cycles. In the type II menstrual cycle, seen in the 3 animals of group B, 2 animals of group C, and in all the 7 animals of group D, the mid-cycle bLH peak was abolished and the progesterone levels during phase II of the cycle were significantly lower than in the controls, indicative of poor luteal function. In the type III menstrual cycle seen in the remaining monkeys, the serum endocrine profile did not differ from that seen in the controls. Thus, the present studies indicate that the intranasal administration of progesterone shows a dose-response effect with respect to the suppression of the oestradiol induced mid-cycle surge of bLH. Suppression of the mid-cycle bLH peak resulted in anovulatory cycles or ovulatory cycles with poor luteal function.
50
Tamanini, C., M. E. Crowder, and T. M. Nett. "Effects of oestradiol and progesterone on pulsatile secretion of luteinizing hormone in ovariectomized ewes." Acta Endocrinologica 111, no. 2 (February 1986): 172–78. http://dx.doi.org/10.1530/acta.0.1110172.
Full textAbstract:
Abstract. The effect of treatment with oestradiol, progesterone, a combination of the two steroids or no steroids on pulsatile release of luteinizing hormone (LH) was examined in ovariectomized ewes. Beginning 3 days after ovariectomy, 5 ewes were assigned to each of the following treatment groups: 0.7 mg oestradiol, 16 mg progesterone, 0.7 mg oestradiol plus 16 mg progesterone or no steroid. All treatments were administered twice daily for 3 weeks in a 0.5 ml injection of ethanol given sc. After 2 weeks of treatment and 1, 4, 8, 16 and 32 days after the treatment period ended, blood samples were obtained from all ewes at 10-min intervals for a 6-h period. At the end of the 6-h period, 100 μg gonadotrophin-releasing hormone (GnRH) was injected iv and blood samples were collected at 15 min intervals for an additional 5 h to estimate the relative pituitary content of LH. Ovariectomized ewes receiving no steroid presented regular pulses of LH at frequency of four to five pulses during a 6-h sampling period. Treatment with progesterone alone decreased the frequency of pulsatile release of LH to approximately 1 pulse/6 h, but did not affect the amplitudes of the pulses of LH. Recovery of pulsatile release of LH to a frequency of four or five pulses of LH in a 6-h period was complete between 16 and 32 days after treatment ended in progesterone-treated ewes. Oestradiol, administered alone or with progesterone, resulted in a decrease in both the frequency and the amplitude of pulses of LH compared to control ewes and a decrease in GnRH-induced release of LH. In these groups, the GnRH-induced release of LH had returned to normal by 32 days after cessation of treatment. Although frequency and amplitude of endogenous pulses had increased by 32 days post-treatment, neither parameter had returned to normal. These data suggest that oestradiol exerts an inhibitory effect on the pituitary by decreasing the content of LH to a level which precludes pulsatile release of LH. Progesterone, in contrast, may inhibit the frequency of release of pulses of LH by reducing the frequency of pulsatile release of GnRH from the hypothalamus.