Journal articles: '3, 3', 5-triiodo-l-thyronine(t3)'

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Chatonnet, Fabrice, Frédéric Picou, Teddy Fauquier, and Frédéric Flamant. "Thyroid Hormone Action in Cerebellum and Cerebral Cortex Development." Journal of Thyroid Research 2011 (2011): 1–8. http://dx.doi.org/10.4061/2011/145762.

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Thyroid hormones (TH, including the prohormone thyroxine (T4) and its active deiodinated derivative 3,,5-triiodo-L-thyronine (T3)) are important regulators of vertebrates neurodevelopment. Specific transporters and deiodinases are required to ensure T3 access to the developing brain. T3 activates a number of differentiation processes in neuronal and glial cell types by binding to nuclear receptors, acting directly on transcription. Only few T3 target genes are currently known. Deeper investigations are urgently needed, considering that some chemicals present in food are believed to interfere with T3 signaling with putative neurotoxic consequences.

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Markova, Natalyia, Anton Chernopiatko, Careen A. Schroeter, Dmitry Malin, Aslan Kubatiev, Sergey Bachurin, João Costa-Nunes, Harry M. W. Steinbusch, and Tatyana Strekalova. "Hippocampal Gene Expression of Deiodinases 2 and 3 and Effects of 3,5-Diiodo-L-Thyronine T2 in Mouse Depression Paradigms." BioMed Research International 2013 (2013): 1–14. http://dx.doi.org/10.1155/2013/565218.

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Central thyroid hormone signaling is important in brain function/dysfunction, including affective disorders and depression. In contrast to 3,3′,5-triiodo-L-thyronine (T3), the role of 3,5-diiodo-L-thyronine (T2), which until recently was considered an inactive metabolite of T3, has not been studied in these pathologies. However, both T3 and T2 stimulate mitochondrial respiration, a factor counteracting the pathogenesis of depressive disorder, but the cellular origins in the CNS, mechanisms, and kinetics of the cellular action for these two hormones are distinct and independent of each other. Here, Illumina and RT PCR assays showed that hippocampal gene expression of deiodinases 2 and 3, enzymes involved in thyroid hormone regulation, is increased in resilience to stress-induced depressive syndrome and after antidepressant treatment in mice that might suggest elevated T2 and T3 turnover in these phenotypes. In a separate experiment, bolus administration of T2 at the doses 750 and 1500 mcg/kg but not 250 mcg/kg in naive mice reduced immobility in a two-day tail suspension test in various settings without changing locomotion or anxiety. This demonstrates an antidepressant-like effect of T2 that could be exploited clinically. In a wider context, the current study suggests important central functions of T2, whose biological role only lately is becoming to be elucidated.

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Petersen, K. F., G. W. Cline, J. B. Blair, and G. I. Shulman. "Substrate cycling between pyruvate and oxaloacetate in awake normal and 3,3'-5-triiodo-L-thyronine-treated rats." American Journal of Physiology-Endocrinology and Metabolism 267, no. 2 (August 1, 1994): E273—E277. http://dx.doi.org/10.1152/ajpendo.1994.267.2.e273.

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Substrate cycling between pyruvate and oxaloacetate was assessed in awake 24-h fasted normal and triiodothyronine (T3)-treated rats. After a 20- or 60-min infusion of [3-13C]alanine (99% enriched, 12 mg/min) the 13C enrichments of liver glucose and alanine carbons were analyzed by 13C and 1H nuclear magnetic resonance spectroscopy and gas chromatography-mass spectrometry. Substrate cycling from phosphoenolpyruvate to pyruvate [via pyruvate kinase (PK)] and from oxaloacetate to pyruvate [via malic enzyme (ME)] relative to the pyruvate carboxylase (PC) flux [i.e., (PK+ME)/PC] was assessed by the ratio of the 13C enrichment of C-2 alanine relative to that in C-5 glucose. In the normal rats (PK+ME)/PC was 0.26 +/- 0.07 (n = 7, t = 20 min) and 0.37 +/- 0.08 (n = 4, t = 60 min). In the T3-treated rats the (PK+ME)/PC increased four- to fivefold to 1.03 +/- 0.19 (n = 8, t = 20 min) and to 1.83 +/- 0.19 (n = 3, t = 60 min) (P < 0.05 vs. normal rats). The liver enzyme activity of PK did not change with T3 treatment (normal 14.22 +/- 5.25 U/g liver vs. T3 treated 13.40 +/- 1.10 U/g liver), whereas both the enzyme activity ratio of PK (normal 0.47 +/- 0.15 vs. T3 treated 0.77 +/- 0.03, P < 0.05) and the activity of ME (normal 0.89 +/- 0.30 U/g liver vs. T3 treated 4.25 +/- 0.60 U/g liver, P < 0.05) increased with T3 treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

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Silvestri, Elena, Assunta Lombardi, Maria Coppola, Alessandra Gentile, Federica Cioffi, Rosalba Senese, Fernando Goglia, Antonia Lanni, Maria Moreno, and Pieter de Lange. "Differential Effects of 3,5-Diiodo-L-Thyronine and 3,5,3’-Triiodo-L-Thyronine On Mitochondrial Respiratory Pathways in Liver from Hypothyroid Rats." Cellular Physiology and Biochemistry 47, no. 6 (2018): 2471–83. http://dx.doi.org/10.1159/000491620.

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Background/Aims: Both 3,5-diiodo-L-thyronine (3,5-T2) and 3,5,3’-triiodo-L-tyronine (T3) affect energy metabolism having mitochondria as a major target. However, the underlying mechanisms are poorly understood. Here, using a model of chemically induced hypothyroidism in male Wistar rats, we investigated the effect of administration of either 3,5-T2 or T3 on liver oxidative capacity through their influence on mitochondrial processes including: proton-leak across the mitochondrial inner membrane; complex I-, complex II- and glycerol-3-phosphate-linked respiratory pathways; respiratory complex abundance and activities as well as individual complex aggregation into supercomplexes. Methods: Hypothyroidism was induced by propylthiouracil and iopanoic acid; 3,5-T2 and T3 were intraperitoneally administered at 25 and 15 µg/100 g BW for 1 week, respectively. Resulting alterations in mitochondrial function were studied by combining respirometry, Blue Native-PAGE followed by in-gel activity, and Western blot analyses. Results: Administration of 3,5-T2 and T3 to hypothyroid (hypo) rats enhanced mitochondrial respiration rate with only T3 effectively stimulating proton-leak (450% vs. Hypo). T3 significantly enhanced complex I (+145% vs. Hypo), complex II (+66% vs. Hypo), and glycerol-3 phosphate dehydrogenase (G3PDH)-linked oxygen consumptions (about 6- fold those obtained in Hypo), while 3,5-T2 administration selectively restored Euthyroid values of complex II- and increased G3PDH- linked respiratory pathways (+165% vs. Hypo). The mitochondrial abundance of all respiratory complexes and of G3PDH was increased by T3 administration whereas 3,5-T2 only increased complex V and G3PDH abundance. 3,5-T2 enhanced complex I and complex II in gel activities with less intensity than did T3, and T3 also enhanced the activity of all other respiratory complexes tested. In addition, only T3 enhanced individual respiratory component complex assembly into supercomplexes. Conclusions: The reported data highlight novel molecular mechanisms underlying the effect elicited by iodothyronine administration to hypothyroid rats on mitochondrial processes related to alteration in oxidative capacity in the liver. The differential effects elicited by the two iodothyronines indicate that 3,5-T2, by influencing the kinetic properties of specific mitochondrial respiratory pathways, would promote a rapid response of the organelle, while T3, by enhancing the abundance of respiratory chain component and favoring the organization of respiratory chain complex in supercomplexes, would induce a slower and prolonged response of the organelle.

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Lin, Hung-Yun, Mingzeng Sun, Heng-Yuan Tang, Cassie Lin, Mary K. Luidens, Shaker A. Mousa, Sandra Incerpi, George L. Drusano, Faith B. Davis, and Paul J. Davis. "l-Thyroxine vs. 3,5,3′-triiodo-l-thyronine and cell proliferation: activation of mitogen-activated protein kinase and phosphatidylinositol 3-kinase." American Journal of Physiology-Cell Physiology 296, no. 5 (May 2009): C980—C991. http://dx.doi.org/10.1152/ajpcell.00305.2008.

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3,5,3′-Triiodo-l-thyronine (T3), but not l-thyroxine (T4), activated Src kinase and, downstream, phosphatidylinositol 3-kinase (PI3-kinase) by means of an αvβ3 integrin receptor on human glioblastoma U-87 MG cells. Although both T3 and T4 stimulated extracellular signal-regulated kinase (ERK) 1/2, activated ERK1/2 did not contribute to T3-induced Src kinase or PI3-kinase activation, and an inhibitor of PI3-kinase, LY-294002, did not block activation of ERK1/2 by physiological concentrations of T3 and T4. Thus the PI3-kinase, Src kinase, and ERK1/2 signaling cascades are parallel pathways in T3-treated U-87 MG cells. T3 and T4 both caused proliferation of U-87 MG cells; these effects were blocked by the ERK1/2 inhibitor PD-98059 but not by LY-294002. Small-interfering RNA knockdown of PI3-kinase confirmed that PI3-kinase was not involved in the proliferative action of T3 on U-87 MG cells. PI3-kinase-dependent actions of T3 in these cells included shuttling of nuclear thyroid hormone receptor-α (TRα) from cytoplasm to nucleus and accumulation of hypoxia-inducible factor ( HIF)- 1α mRNA; LY-294002 inhibited these actions. Results of studies involving αvβ3 receptor antagonists tetraiodothyroacetic acid (tetrac) and Arg-Gly-Asp (RGD) peptide, together with mathematical modeling of the kinetics of displacement of radiolabeled T3 from the integrin by unlabeled T3 and by unlabeled T4, are consistent with the presence of two iodothyronine receptor domains on the integrin. A model proposes that one site binds T3 exclusively, activates PI3-kinase via Src kinase, and stimulates TRα trafficking and HIF- 1α gene expression. Tetrac and RGD peptide both inhibit T3 action at this site. The second site binds T4 and T3, and, via this receptor, the iodothyronines stimulate ERK1/2-dependent tumor cell proliferation. T3 action here is inhibited by tetrac alone, but the effect of T4 is blocked by both tetrac and the RGD peptide.

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Scapin, Sergio, Silvia Leoni, Silvana Spagnuolo, Anna Maria Fiore, and Sandra Incerpi. "Short-term effects of thyroid hormones on Na+-K+-ATPase activity of chick embryo hepatocytes during development: focus on signal transduction." American Journal of Physiology-Cell Physiology 296, no. 1 (January 2009): C4—C12. http://dx.doi.org/10.1152/ajpcell.90604.2007.

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Nongenomic effects of thyroid hormones on Na+-K+-ATPase activity were studied in chick embryo hepatocytes at two different developmental stages, 14 and 19 days of embryonal age, and the signal transduction pathways involved were characterized. Our data showed the following. 1) 3,5,3′-Triiodo-l-thyronine (T3) and 3,5-diiodo-l-thyronine (3,5-T2) rapidly induced a transient inhibitory effect on the Na+-K+-ATPase; the extent and duration depended on the developmental age of the cells. 2) 3,5-T2 behaved as a true hormone and fully mimicked the effect of T3. 3) Thyroxine had no effect at any of the developmental stages. 4) The inhibition of Na+-K+-ATPase was mediated by activation of protein kinase A, protein kinase C, and phosphoinositide 3-kinase, suggesting several modes of modulation of ATPase activity through phosphorylation at different sites. 5) The MAPK pathway did not seem to be involved in the early phase of hormone treatment. 6) The nonpermeant analog T3-agarose inhibited Na+-K+-ATPase activity in the same way as T3, confirming that hormone signaling initiated at a receptor on the plasma membrane. From these results, it can be concluded that the cell response mechanisms change rapidly and drastically within the early phase of embryo growth. The differences found at the two stages probably reflect the different roles of thyroid hormones during development and differentiation.

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HALPERIN, YITZCHAK, LAWRENCE E. SHAPIRO, and MARTIN I. SURKS. "Medium 3,5,3′-Triiodo-L-thyronine (T3) and T3Generated from L-Thyroxine Are Exchangeable in Cultured GC cells*." Endocrinology 127, no. 3 (September 1990): 1050–56. http://dx.doi.org/10.1210/endo-127-3-1050.

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Brown, S. B., R. E. Evans, and Toshiaki J. Hara. "Interrenal, Thyroidal, Carbohydrate, and Electrolyte Responses in Rainbow Trout (Salmo gairdneri) during Recovery from the Effects of Acidification." Canadian Journal of Fisheries and Aquatic Sciences 43, no. 3 (March 1, 1986): 714–18. http://dx.doi.org/10.1139/f86-087.

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Exposure to acid-treated water (H2SO4, pH 4.76) for 21 d increased plasma glucose, protein, and cortisol levels and interrenal nuclear diameter and decreased plasma electrolytes (Na+, Cl−) and osmolality in immature rainbow trout (Salmo gairdneri). Plasma L-thyroxine (T4), 3,5,3′-triiodo-L-thyronine (T3), or their ratio (T4:T3) were not altered by the acid treatment. Following termination of acid exposure, return to control levels was achieved within 1 d by plasma protein, 3 d by plasma cortisol, glucose, sodium, chloride, and osmolality, and 7 d by interrenal nuclear diameter. Thus, within 1 wk the studied aspects of the plasma fluid compartment had recovered from the effects of acid exposure.

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Monk, Julie A., Natalie A. Sims, Katarzyna M. Dziegielewska, Roy E. Weiss, Robert G. Ramsay, and Samantha J. Richardson. "Delayed development of specific thyroid hormone-regulated events in transthyretin null mice." American Journal of Physiology-Endocrinology and Metabolism 304, no. 1 (January 1, 2013): E23—E31. http://dx.doi.org/10.1152/ajpendo.00216.2012.

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Thyroid hormones (THs) are vital for normal postnatal development. Extracellular TH distributor proteins create an intravascular reservoir of THs. Transthyretin (TTR) is a TH distributor protein in the circulatory system and is the only TH distributor protein synthesized in the central nervous system. We investigated the phenotype of TTR null mice during development. Total and free 3′,5′,3,5-tetraiodo-l-thyronine (T4) and free 3′,3,5-triiodo-l-thyronine (T3) in plasma were significantly reduced in 14-day-old (P14) TTR null mice. TTR null mice also displayed a delayed suckling-to-weaning transition, decreased muscle mass, delayed growth, and retarded longitudinal bone growth. In addition, ileums from postnatal day 0 (P0) TTR null mice displayed disordered architecture and contained fewer goblet cells than wild type. Protein concentrations in cerebrospinal fluid from P0 and P14 TTR null mice were higher than in age-matched wild-type mice. In contrast to the current literature based on analyses of adult TTR null mice, our results demonstrate that TTR has an important and nonredundant role in influencing the development of several organs.

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Hercbergs, Aleck A., David H. Garfield, and Osnat Ashur-Fabian. "Triiodothyronine [T3]-induced hypothyroxinemia: Response and survival in a compassionate care cancer patient population." Journal of Clinical Oncology 30, no. 15_suppl (May 20, 2012): e19573-e19573. http://dx.doi.org/10.1200/jco.2012.30.15_suppl.e19573.

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e19573 Background: Increased survival under chemically induced hypothyroidism has been reported in cancer patients with poor prognosis, but the associated morbidity can deter patient compliance. Acting via a receptor site upon the plasma membrane avβ3 integrin, L-thyroxine (T4) in physiological concentrations non-genomically activates mitogenesis and neo-angiogenesis of cancer cells and proliferating vascular endothelium. Occlusion of the receptor by tetraiodothyroacetic acid (tetrac), a T4 derivative, induces apoptosis, inhibits angiogenesis and enhances chemotherapy and radiation. 3, 5, 3’-Triiodo-L-thyronine (T3) in physiological concentrations is significantly less mitogenic than T4 and inhibits pituitary release of thyrotropin (TSH). Absence of TSH, but with T3 support, depletes circulating T4 without resultant hypothyroidism. Methods: 21 cancer patients at dispersed clinical sites with stage 4 solid tumors and projected limited survival received T3 [n=10] only or with methimazole (MT) [n=9]. Serum TSH, free T4 (FT4) and T3 concentrations were obtained initially, then monthly. FT4 levels below lower normal range were achieved in all patients within 3 to 12 weeks. Results: See Table. Conclusions: T3 treatment with resultant hypothyroxinemia in poor prognosis cancer patients was associated with favorable response rates in 17/19 subjects. Two others with aggressive tumors had extended survival on long-term T3. [Table: see text] [Table: see text] [Table: see text]

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Del Viscovo, Adelaide, Agnese Secondo, Alba Esposito, Fernando Goglia, Maria Moreno, and Lorella M. T. Canzoniero. "Intracellular and plasma membrane-initiated pathways involved in the [Ca2+]i elevations induced by iodothyronines (T3 and T2) in pituitary GH3 cells." American Journal of Physiology-Endocrinology and Metabolism 302, no. 11 (June 1, 2012): E1419—E1430. http://dx.doi.org/10.1152/ajpendo.00389.2011.

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The role of 3,5,3′-triiodo-l-thyronine (T3) and its metabolite 3,5-diiodo-l-thyronine (T2) in modulating the intracellular Ca2+ concentration ([Ca2+]i) and endogenous nitric oxide (NO) synthesis was evaluated in pituitary GH3 cells in the absence or presence of extracellular Ca2+. When applied in Ca2+-free solution, T2 and T3 increased [Ca2+]i, in a dose-dependent way, and NO levels. Inhibition of neuronal NO synthase by NG-nitro-l-arginine methyl ester and l- n5-(1-iminoethyl)ornithine hydrochloride significantly reduced the [Ca2+]i increase induced by T2 and T3. However, while depletion of inositol trisphosphate-dependent Ca2+ stores did not interfere with the T2- and T3-induced [Ca2+]i increases, the inhibition of phosphatidylinositol 3-kinase by LY-294002 and the dominant negative form of Akt mutated at the ATP binding site prevented these effects. Furthermore, the mitochondrial protonophore carbonyl cyanide 4-(trifluoromethoxy)phenylhydrazone prevented the increases in both [Ca2+]i and NO elicited by T2 or T3. Interestingly, rotenone blocked the early [Ca2+]i increases elicited by T2 and T3, while antimycin prevented only that elicited by T3. Inhibition of mitochondrial Na+/Ca2+ exchanger by CGP37157 significantly reduced the [Ca2+]i increases induced by T2 and T3. In the presence of extracellular calcium (1.2 mM), under carbonyl cyanide 4-(trifluoromethoxy)phenylhydrazone, T2 and T3 increased both [Ca2+]i and intracellular Na+ concentration; nimodipine reduced the [Ca2+]i increases elicited by T2 and T3, but inhibition of NO synthase and blockade of the Na+/H+ pump by 5-( N-ethyl- N-isopropyl)amiloride prevented only that elicited by T3; and CB-DMB, bisindolylmaleimide, and LY-294002 (inhibitors of the Na+/Ca2+ exchanger, PKC, and phosphatidylinositol 3-kinase, respectively) failed to modify the T2- and T3-induced effects. Collectively, the present results suggest that T2 and T3 exert short-term nongenomic effects on intracellular calcium and NO by modulating plasma membrane and mitochondrial pathways that differ between these iodothyronines.

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Goglia, Fernando, Elena Silvestri, and Antonia Lanni. "Thyroid Hormones and Mitochondria." Bioscience Reports 22, no. 1 (February 1, 2002): 17–32. http://dx.doi.org/10.1023/a:1016056905347.

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Because of their central role in the regulation of energy-transduction, mitochondria, the major site of oxidative processes within the cell, are considered a likely subcellular target for the action that thyroid hormones exert on energy metabolism. However, the mechanism underlying the regulation of basal metabolic rate (BMR) by thyroid hormones still remains unclear. It has been suggested that these hormones might uncouple substrate oxidation from ATP synthesis, but there are no clear-cut data to support this idea. Two iodothyronines have been identified as effectors of the actions of thyroid hormones on energy metabolism: 3',3,5-triiodo-L-thyronine (T3) and 3,5-diiodo-L-thyronine (T2). Both have significant effects on BMR, but their mechanisms of action are not identical. T3 acts on the nucleus to influence the expression of genes involved in the regulation of cellular metabolism and mitochondria function; 3,5-T2, on the other hand, acts by directly influencing the mitochondrial energy-transduction apparatus. A molecular determinant of the effects of T3 could be uncoupling protein-3 (UCP-3), while the cytochrome-c oxidase complex is a possible target for 3,5-T2. In conclusion, it is likely that iodothyronines regulate energy metabolism by both short-term and long-term mechanisms, and that they act in more than one way in affecting mitochondrial functions.

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Ishaq, Mohammad, and Ven Natarajan. "RNA-activated protein kinase differentially modulates innate immune response mediated by supraphysiological concentrations of thyroid hormone." Innate Immunity 26, no. 8 (September 13, 2020): 746–58. http://dx.doi.org/10.1177/1753425920955214.

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Nuclear hormone receptor ligands are known to modulate innate immunity by dampening the immune response induced by pathogens. Here, we report that unlike other ligands, 3,3′,5-triiodo-l-thyronine (T3) induced the type 1 IFN response and expression of IFN-stimulated genes (ISGs). T3 action was found to be significantly amplified at supraphysiological concentrations (SPC) and in combination with double-stranded RNA mimic polyinosinic–polycytidylic acid. Induction by T3 was due to non-genomic mechanisms involving integrin binding, calcium mobilization, and phosphatidyl-inositol 3-kinase–AKT pathways, but was independent of TLR3, RIG-I, and IFN-β1 pathways. Whereas siRNA-induced knockdown of RNA-activated protein kinase (PKR) was found to abrogate the T3-induced expression of select ISGs, expression of other T3-induced ISGs was strongly induced by PKR knockdown, indicating the differential role of PKR in modulating T3 action. Together, we describe a novel role of T3 in modulating the innate immune response and identify the importance of PKR in regulating T3-induced immune activation. These findings have important implications in the basic understanding of the mechanisms of T3 function at SPCs and crosstalk involved in the thyroid hormone function and the innate immune response.

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Johnston, C. E., C. Gordillo, and J. G. Eales. "Transition from a hatchery to a laboratory environment induces inner-ring monodeiodination pathways for thyroid hormones in liver of rainbow trout, Oncorhynchus mykiss." Canadian Journal of Zoology 74, no. 12 (December 1, 1996): 2178–83. http://dx.doi.org/10.1139/z96-246.

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In laboratory-acclimated rainbow trout (Oncorhynchus mykiss) the main hepatic deiodination pathway for thyroid hormones is L-thyroxine (T4) outer-ring deiodination (T4ORD), which produces biologically active 3,5,3′-triiodo-L-thyronine (T3); T4 inner-ring deiodination (T4IRD) as well as T3ORD and T3IRD activities are low or undetectable. Surprisingly, trout transported 48 h previously from a local hatchery to the laboratory demonstrated not only low T4ORD activity but also significant T4IRD and T3IRD activities. To test if the transition from hatchery to laboratory environment had induced the unexpected inner-ring deiodinations, we measured hepatic deiodinase activities over the same time frame in trout recently transported to the laboratory and also in trout retained undisturbed at the hatchery. Undisturbed hatchery trout showed typical hepatic deiodinase function: T4ORD activity predominated, while T3IRD, T4IRD, and T3ORD activities were basal. However, after 1–3 days in the laboratory, hepatic T4ORD activity was reduced and T4IRD and T3IRD activities were increased. By 5 days, deiodinase activities of laboratory trout reverted to the levels of hatchery trout. We conclude that physical disturbance can temporarily depress thyroidal status by simultaneously decreasing hepatic production of biologically active T3 and inducing degradation of T4 and T3.

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Eales, J. G., G. Van Der Kraak, J. P. Chang, and R. J. Omeljaniuk. "Effects of temperature on triiodothyronine plasma levels, kinetics, and hepatocyte nuclear binding in rainbow trout, Salmo gairdneri." Canadian Journal of Zoology 64, no. 12 (December 1, 1986): 2658–64. http://dx.doi.org/10.1139/z86-386.

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Plasma levels of 3,5,3′-triiodo-L-thyronine (T3), plasma T3 kinetics, and properties of in vivo T3 binding to saturable hepatocyte nuclear sites were studied in fed immature rainbow trout maintained at 12 °C and then held for up to 14 d at 5, 11–12, or 19 °C. Elevation (19 °C) or depression (5 °C) of plasma T3 occurred during the first 3 h following abrupt transfer from 11 °C, but from 12 h to 7 d, plasma T3 did not differ significantly among the three temperatures. In contrast, the plasma T3 degradation rate increased fourfold from 5 to 19 °C largely because of an increased fractional rate of turnover of the plasma T3 pool. Outer-ring deiodination of T3 was negligible at 5 and 12 °C and slight at 19 °C. Temperature did not influence the proportion of [125I]T3 lost via the enterohepatic route. Uptake of [125I]T3 into the liver and liver nuclear fraction was most rapid at 19 °C, intermediate at 12 °C, and least rapid at 5 °C. Saturable nuclear binding of [125I]T3 occurred at all temperatures. The apparent affinity of T3 for hepatic nuclear sites was similar at 12 and 19 °C but lower at 5 °C; the apparent site capacity underwent no significant change with temperature. In conclusion, over the range of 5 to 19 °C there are marked increases in plasma T3 clearance, rate of T3 uptake from plasma to liver, and rate of T3 uptake by the liver nuclear fraction, but relatively small changes in plasma T3 level, proportion of T3 excreted via the enterohepatic route, and properties of the saturable T3-binding nuclear sites.

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Davis, Paul J., Faith B. Davis, Hung-Yun Lin, Shaker A. Mousa, Min Zhou, and Mary K. Luidens. "Translational implications of nongenomic actions of thyroid hormone initiated at its integrin receptor." American Journal of Physiology-Endocrinology and Metabolism 297, no. 6 (December 2009): E1238—E1246. http://dx.doi.org/10.1152/ajpendo.00480.2009.

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A thyroid hormone receptor on integrin αvβ3 that mediates cell surface-initiated nongenomic actions of thyroid hormone on tumor cell proliferation and on angiogenesis has been described. Transduction of the hormone signal into these recently recognized proliferative effects is by extracellular-regulated kinases 1/2 (ERK1/2). Other nongenomic actions of the hormone may be transduced by phosphatidylinositol 3-kinase (PI3K) and are initiated in cytoplasm or at the cell surface. PI3K-mediated effects are important to angiogenesis or other recently appreciated cell functions but apparently not to tumor cell division. For those actions of thyroid hormone [l-thyroxine (T4) and 3,3′-5-triiodo-l-thyronine (T3)] that begin at the integrin receptor, tetraiodothyroacetic acid (tetrac) is an inhibitor of and probe for the participation of the receptor in downstream intracellular events. In addition, tetrac has actions initiated at the integrin receptor that are unrelated to inhibition of the effects of T4 and T3 but do involve gene transcription in tumor cells. Discussed here are the implications of translating these nongenomic mechanisms of thyroid hormone analogs into clinical cancer cell biology, tumor-related angiogenesis, and modulation of angiogenesis that is not related to cancer.

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Sweeting, R. M., and J. G. Eales. "The effects of fasting and feeding on hepatic thyroxine 5′-monodeiodinase activity in the rainbow trout, Oncorhynchus mykiss." Canadian Journal of Zoology 70, no. 8 (August 1, 1992): 1516–25. http://dx.doi.org/10.1139/z92-209.

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The effects of fasting and feeding on the activity and kinetics of the hepatic microsomal L-thyroxine (T4) 5′-monodeiodinase enzyme system (5′D) responsible for generating 3,5,3′-triiodo-L-thyronine (T3) were studied in immature rainbow trout held on a 12 h L: 12 h D photocycle at 12 °C. The 5′D activity was determined from the essentially stoichiometric production of 125I− and 3,5,[3′-125I]T3 as the primary labeled materials from 3,5,[3′-125I],5′-T4 substrate, as judged by LH-20 Sephadex chromatography and HPLC. Relative to trout fed 2% body weight∙day−1 (2% ration), fasting depressed 5′D activity within 3 days. By 7 days a basal 5′D level was reached, which persisted for at least 20 days. In trout fed a 0.8% ration, fasting for 8 days depressed 5′D activity to a level lower than that of trout fed a 2% prefasting ration, suggesting 5′D response to energy reserves. However, following 8 days fasting, refeeding for 7 days reinstalled 5′D activity, regardless of prior maintenance on a 0.8 or 2% ration. There was a strong positive correlation between body weight gain and 5′D activity for trout fed rations of 0, 0.3, 0.6, 1, 2, or 3% for 14 days. Kinetic analyses showed that change in 5′D activity was due mainly to change in Vmax (quantity of functional enzyme units). However, fasting also decreased Km (Michaelis–Menten constant), suggesting the presence of a 5′D form with a higher T4 affinity. The 5′D activity was significantly correlated with the blood plasma T3 level, but not with the plasma T4 level. We conclude that (i) hepatic 5′D responds rapidly to both food deprivation and feeding and is also sensitive to energy reserves, (ii) the response primarily involves the level of functional 5′D units but some change in enzyme form may also occur, and (iii) the high positive correlations between 5′D activity, plasma T3 level, and gain in body weight are consistent with a role of hepatic 5′D in generating systemic T3, which in turn may regulate somatic growth.

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Segal, J. "Opposite regulatory effects of cAMP and cGMP on sugar uptake in rat thymocytes." American Journal of Physiology-Endocrinology and Metabolism 252, no. 5 (May 1, 1987): E588—E594. http://dx.doi.org/10.1152/ajpendo.1987.252.5.e588.

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The present study provides several lines of evidence which indicate that in the rat thymocyte adenosine 3',5'-cyclic monophosphate (cAMP) and guanosine 3',5-cyclic monophosphate (cGMP) induce opposing regulatory effects on 2-deoxyglucose (2-DG) uptake; cAMP is stimulatory, whereas cGMP is inhibitory. First, the cyclic nucleotide analogues dibutyryl cAMP (dBcAMP) and dibutyryl cGMP (dBcGMP) produced a dose-related increase and decrease in thymocyte 2-DG uptake, respectively. Second, 3,5,3'-triiodo-L-thyronine (T3) and epinephrine, which increased cellular cAMP concentration but had no effect on cellular cGMP concentration, increased 2-DG uptake in the rat thymocyte. Third, dBcGMP inhibited the stimulatory effects of dBcAMP, T3, and epinephrine on thymocyte 2-DG uptake. Fourth, prostaglandin E1 and the inhibitors of the cyclic nucleotide phosphodiesterases, 3-isobutyl-1-methylxanthine, theophylline, and caffeine, all increased both cellular cAMP and cGMP concentration but had no effect on 2-DG uptake. Insulin did not change cellular cAMP and cGMP concentration, but produced a dose-related increase in 2-DG uptake by the rat thymocyte. From these results I have concluded that in the rat thymocyte cAMP and cGMP produce opposite effects on sugar uptake and that the effect of certain, but not all, agents on thymocyte sugar uptake results from their modulation of cellular cAMP and cGMP concentration.

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Sayre, Naomi L., Mikaela Sifuentes, Deborah Holstein, Sheue-yann Cheng, Xuguang Zhu, and James D. Lechleiter. "Stimulation of astrocyte fatty acid oxidation by thyroid hormone is protective against ischemic stroke-induced damage." Journal of Cerebral Blood Flow & Metabolism 37, no. 2 (July 20, 2016): 514–27. http://dx.doi.org/10.1177/0271678x16629153.

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We previously demonstrated that stimulation of astrocyte mitochondrial ATP production via P2Y1 receptor agonists was neuroprotective after cerebral ischemic stroke. Another mechanism that increases ATP production is fatty acid oxidation (FAO). We show that in primary human astrocytes, FAO and ATP production are stimulated by 3,3,5 triiodo-l-thyronine (T3). We tested whether T3-stimulated FAO enhances neuroprotection, and show that T3 increased astrocyte survival after either hydrogen peroxide exposure or oxygen glucose deprivation. T3-mediated ATP production and protection were both eliminated with etomoxir, an inhibitor of FAO. T3-mediated protection in vitro was also dependent on astrocytes expressing HADHA (hydroxyacyl-CoA dehydrogenase/3-ketoacyl-CoA thiolase/enoyl-CoA hydratase), which we previously showed was critical for T3-mediated FAO in fibroblasts. Consistent with previous reports, T3-treatment decreased stroke volumes in mice. While T3 decreased stroke volume in etomoxir-treated mice, T3 had no protective effect on stroke volume in HADHA +/− mice or in mice unable to upregulate astrocyte-specific energy production. In vivo, 95% of HADHA co-localize with glial-fibrillary acidic protein, suggesting the effect of HADHA is astrocyte mediated. These results suggest that astrocyte-FAO modulates lesion size and is required for T3-mediated neuroprotection post-stroke. To our knowledge, this is the first report of a neuroprotective role for FAO in the brain.

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20

Ksenzenko, Sergey M., Scott B. Davidson, Amer A. Saba, Alexander P. Franko, Aml M. Raafat, Lawrence N. Diebel, and Scott A. Dulchavsky. "Effect of triiodothyronine augmentation on rat lung surfactant phospholipids during sepsis." Journal of Applied Physiology 82, no. 6 (June 1, 1997): 2020–27. http://dx.doi.org/10.1152/jappl.1997.82.6.2020.

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Ksenzenko, Sergey M., Scott B. Davidson, Amer A. Saba, Alexander P. Franko, Aml M. Raafat, Lawrence N. Diebel, and Scott A. Dulchavsky. Effect of triiodothyronine augmentation on rat lung surfactant phospholipids during sepsis. J. Appl. Physiol. 82(6): 2020–2027, 1997.—Surfactant functional effectiveness is dependent on phospholipid compositional integrity; sepsis decreases this through an undefined mechanism. Sepsis-induced hypothyroidism is commensurate and may be related. This study examines the effect of 3,3′,5-triiodo-l-thyronine (T3) supplementation on surfactant composition and function during sepsis. Male Sprague-Dawley rats underwent sham laparotomy (Sham) or cecal ligation and puncture (CLP) with or without T3supplementation [CLP/T3 (3 ng/h)]. After 6, 12, or 24 h, surfactant was obtained by lavage. Function was assessed by a pulsating bubble surfactometer and in vivo compliance studies. Sepsis produced a decrease in surfactant phosphatidylglycerol and phosphatidic acid, with an increase in lesser surface-active lipids phosphatidylserine and phosphatidylinositol. Phosphatidylcholine content was not significantly changed. Sepsis caused an alteration in the fatty acid composition and an increase in saturation in most phospholipids. Hormonal replacement attenuated these changes. Lung compliance and surfactant adsorption were reduced by sepsis and maintained by T3treatment. Thyroid hormone may have an active role in lung functional preservation through maintenance of surfactant homeostasis during sepsis.

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21

Yonemura, K., L. Cheng, B. Sacktor, and J. L. Kinsella. "Stimulation by thyroid hormone of Na+-H+ exchange activity in cultured opossum kidney cells." American Journal of Physiology-Renal Physiology 258, no. 2 (February 1, 1990): F333—F338. http://dx.doi.org/10.1152/ajprenal.1990.258.2.f333.

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Cultured opossum kidney (OK) cells were used to determine whether thyroid hormone has a direct stimulatory effect on Na(+)-H+ exchange activity in an intact cellular preparation. Na+ uptake or intracellular pH recovery was measured in confluent monolayer cells following acid loading with NH4Cl. Triiodo-L-thyronine (T3) had no effect on cell number or protein and DNA contents but stimulated amiloride-sensitive Na+ uptake in a dose- and time-dependent manner. Maximal stimulation of Na+ uptake was observed at 10(-7) M T3 and 10(-6) M L-thyroxine (T4) with half-maximal effects at 10(-9) M T3 and 3 x 10(-8) M T4. The T3 specific binding capacity of OK cells was 96 +/- 15 fmol/mg DNA with a KD of 1.1 +/- 0.2 x 10(-9) M T3. Neither T3 nor T4 had any effect on amiloride-insensitive Na+ uptake. In kinetic studies of Na+ uptake, T3 increased the Vmax from 123 +/- 22 to 157 +/- 24 nmol.mg-1.min-1 without changing the Michaelis-Menten kinetics (Km) for Na+ (21 +/- 1 in control and 22 +/- 4 mM in T3-treated cells). Studies of intracellular pH (pHi) showed that the resting pHi and the buffering capacity were unaffected by T3. However, after an acid load, OK cells treated with T3 exhibited a greater rate of Na(+)-dependent pH recovery than untreated control cells. These results indicate that thyroid hormone can stimulate Na(+)-H+ exchange activity directly in renal cell line without apparent changes in pHi, cellular hypertrophy, or hyperplasia.

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Haber, R. S., and J. N. Loeb. "Selective induction of high-ouabain-affinity isoform of Na+-K+-ATPase by thyroid hormone." American Journal of Physiology-Endocrinology and Metabolism 255, no. 6 (December 1, 1988): E912—E919. http://dx.doi.org/10.1152/ajpendo.1988.255.6.e912.

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The administration of thyroid hormone is known to result in an induction of the Na+-K+-adenosinetriphosphatase (Na+-K+-ATPase) in rat skeletal muscle and other thyroid hormone-responsive tissues. Since the Na+-K+-ATPase in a variety of mammalian tissues has recently been reported to exist in at least two forms distinguishable by differing affinities for the inhibitory cardiac glycoside ouabain, we have studied the effects of 3,3',5-triiodo-L-thyronine (T3) treatment on these two forms of the enzyme in rat diaphragm. The inhibition of Na+-K+-ATPase activity in a crude membrane fraction by varying concentrations of ouabain conformed to a biphasic pattern consistent with the presence of two distinct isoforms with inhibition constants (KIs) for ouabain of approximately 10(-7) and 10(-4) M, respectively. Treatment of hypothyroid rats with T3 (50 micrograms/100 g body wt on 3 alternate days) nearly tripled that portion of the Na+-K+-ATPase activity corresponding to the high-ouabain-affinity form (increased by 178 +/- 24%), whereas the enzyme activity corresponding to the low-ouabain-affinity form was only slightly changed (increased by 20 +/- 5%). Measurement of the specific binding of [3H]ouabain to these membranes confirmed the presence of a class of high-affinity ouabain binding sites with a dissociation constant (Kd) of slightly less than 10(-7) M, whose maximal binding capacity was increased by T3 treatment by 185%. The calculated catalytic turnover associated with the high-affinity site was 70-80 molecules ATP hydrolyzed.site-1.s-1 and was unchanged by T3 treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

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23

Brown, S. B., R. E. Evans, H. S. Majewski, G. B. Sangalang, and J. F. Klaverkamp. "Responses of Plasma Electrolytes, Thyroid Hormones, and Gill Histology in Atlantic Salmon (Salmo salar) to Acid and Limed River Waters." Canadian Journal of Fisheries and Aquatic Sciences 47, no. 12 (December 1, 1990): 2431–40. http://dx.doi.org/10.1139/f90-271.

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Sexually maturing Atlantic salmon, Salmo salar, were held, in the acidic (pH range 4.7–5.2) Westfield River, Nova Scotia and in the nearby, less acidic (pH range 5.2–5.6) Medway River. Exposure to Westfield River water in 1985 (149 d) and 1986 (126 d) reduced plasma osmolality, Na+, Cl−, and Ca++ (in females only) concentrations of post-spawning fish compared to those in fish held in the Medway River. There were coincidental increases in plasma K+, glucose, and unidentified osmotic fraction (UOF). Gill tissue showed hyperplasia of primary lamellae epithelium. Together, these findings indicate compromised ionoregulatory ability. Decreased plasma T3 (3,5,3′-triiodo-L-thyronine) suggests altered thyroid function. Westfield River water did not affect plasma T4(L-thyroxine) or protein concentrations. An unintentional handling stress caused even more severely depressed plasma ions and more elevated plasma glucose in Westfield fish in 1985 relative to 1986; Medway fish largely recovered from this stress. These observations indicate that acid-exposed fish may be more sensitive to additional stressors. Limestone treatment of Westfield River water (elevating its pH to Medway values) ameliorated ionoregulatory ability but did not affect plasma T3 and Ca++ (female). A high salt diet (3% NaCl) failed to protect salmon from the effects of acidic water.

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Ojamaa, Kaie, Agnes Kenessey, Rajesh Shenoy, and Irwin Klein. "Thyroid hormone metabolism and cardiac gene expression after acute myocardial infarction in the rat." American Journal of Physiology-Endocrinology and Metabolism 279, no. 6 (December 1, 2000): E1319—E1324. http://dx.doi.org/10.1152/ajpendo.2000.279.6.e1319.

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In a rat model of acute myocardial infarction (MI) produced by coronary artery ligation, thyroid hormone metabolism was altered with significant reductions (54%) in serum triiodo-l-thyronine (T3), the cellular active hormone metabolite. T3 has profound effects on the heart; therefore, rats were treated with T3 after acute MI for 2 or 3 wk, at either replacement or elevated doses, to determine whether cardiac function and gene expression could be normalized. Acute MI resulted in a 50% ( P < 0.001) decrease in percent ejection fraction (%EF) with a 32–35% increase ( P < 0.01) in compensatory left ventricle (LV) hypertrophy. Treatment of the MI animals with either replacement or elevated doses of T3 significantly increased %EF to 64 and 73% of control, respectively. Expression levels of several T3-responsive genes were altered in the hypertrophied LV after MI, including significant decreases in α-myosin heavy chain (MHC), sarcoplasmic reticulum calcium-activated ATPase (SERCA2), and Kv1.5 mRNA, whereas β-MHC and phospholamban (PLB) mRNA were significantly increased. Normalization of serum T3 did not restore expression of all T3-regulated genes, indicating altered T3 responsiveness in the postinfarcted myocardium. Although β-MHC and Kv1.5 mRNA content was returned to control levels, α-MHC and SERCA2 were unresponsive to T3 at replacement doses, and only at higher doses of T3 was α-MHC mRNA returned to control values. The present study showed that acute MI in the rat was associated with a fall in serum T3 levels, LV dysfunction, and altered expression of T3-responsive genes and that T3 treatment significantly improved cardiac function, with normalization of some, but not all, of the changes in gene expression.

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25

Haber, R. S., C. M. Wilson, S. P. Weinstein, A. Pritsker, and S. W. Cushman. "Thyroid hormone increases the partitioning of glucose transporters to the plasma membrane in ARL 15 cells." American Journal of Physiology-Endocrinology and Metabolism 269, no. 3 (September 1, 1995): E605—E610. http://dx.doi.org/10.1152/ajpendo.1995.269.3.e605.

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The stimulation of glucose transport by 3,5,3'-triiodo-L-thyronine (T3) in the liver-derived ARL 15 cell line is only partly attributable to increased GLUT-1 glucose transporter gene expression. To test the hypothesis that T3 increases the partitioning of GLUT-1 to the cell surface, we quantitated surface GLUT-1 using the photolabel ATB-[3H]BMPA. In control cells only approximately 20% of total cellular GLUT-1 was present at the cell surface. T3 treatment (100 nM) for 6 h increased the rate of 2-deoxy-[3H]glucose (2-DG) uptake by 30, 92, and 95% in three experiments and increased surface GLUT-1 photolabeling by 17, 81, and 72%, respectively, with no increase in total cellular GLUT-1. T3 treatment for 48 h increased 2-DG uptake by 143, 172, and 216% in three experiments and increased cell surface GLUT-1 photolabeling by 88, 161, and 184%, respectively, with smaller increases in total cellular GLUT-1. T3 treatment for 48 h thus increased the fraction of cellular GLUT-1 at the plasma membrane from 21 +/- 2 to 35 +/- 3% (SE). We conclude that most of the early (6-h) stimulation of glucose transport by T3 in ARL 15 cells is mediated by an increase in the partitioning of GLUT-1 to the plasma membrane. With more chronic T3 treatment (48 h), the enhanced surface partitioning of GLUT-1 is persistent and is superimposed on an increase in total cellular GLUT-1, accounting for a further increase in glucose transport.

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Flett, P. A., G. Van Der Kraak, K. R. Munkittrick, and J. F. Leatherland. "Overripening as the cause of low survival to hatch in Lake Erie coho salmon (Oncorhynchus kisutch) embryos." Canadian Journal of Zoology 74, no. 5 (May 1, 1996): 851–57. http://dx.doi.org/10.1139/z96-099.

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We investigated the cause of the low survival to hatch of embryos of coho salmon (Oncorhynchus kisutch) from the Fairview, Pennsylvania, stock in Lake Erie. In 1988, survival to hatch of this stock was only 42%, whereas another Great Lakes coho salmon stock of similar genetic origin had an 84% survival to hatch. Laboratory cross-fertilization studies between the Fairview stock and a reference Lake Erie stock from Simcoe, Ontario, showed that eggs from the Fairview stock were the probable source of the low fertility. The presence of overripe eggs in Fairview females was associated with poor fertilization and low survival to hatch. Plasma gonadotropin II levels were similar in preovulatory females taken from the Fairview and Simcoe stocks, but testosterone and 17α, 20β-dihydroxy-4-pregnen-3-one levels were significantly lower in the Fairview females. Increasing the triiodo-L-thyronine (T3) content of the eggs by the administration of T3 to the preovulatory females did not enhance egg fertility. We propose that the low survival to hatch of the Fairview embryos is due to delayed oocyte maturation and ovulation and vent maturation, which may have been caused by exposure of the Fairview salmon to warmer water during the period of late ovarian maturation and migration.

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Huszenicza, Gy, M. Kulcsár, S. J. Dieleman, P. Kóródi, J. Bartyik, P. Rudas, P. Ribiczei-Szabó, J. A. Nikolic, H. Samanch, and I. Ivanov. "Hormone and metabolite profiles as well as the onset of ovarian cyclicity in dairy cows suffering from various forms of ketosis." BSAP Occasional Publication 26, no. 2 (September 2001): 399–404. http://dx.doi.org/10.1017/s0263967x00033991.

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AbstractThe involvement of adrenocortical and thyroid hormones in the pathogenesis of ketosis as well as the ovarian consequences of this metabolic disorder were studied in ≥2 parity cows (n=199) in 3 large scale dairy herds. To compare the plasma / serum concentrations of certain hormones [Cortisol, thyroxin (T4), triiodo-thyronine (T3), insulin, isulin-like growth factor-1 (IGF-l)J and metabolites [glucose (G), acetoacetic acid (ACAC), βOH-butyrate (BHB), non-esterified fatty acid (NEFA), trigliceride (TG), total cholesterol (TCh)J, and the activity of aspartate aminotransferase (AST), blood samples were taken 1 to 3 days after calving and again at 7-day intervals on four other occasions. The ACTH-challenged Cortisol responsiveness and the TRH-induced T4/T3 increase were determined between days 1 to 3 and again between days 28 to 35. The resumption of ovarian cyclicity was followed up by individual progesterone (P4) profiles based on milk samples taken 3 times a week for about 80 to 85 days postpartum. A concentration of 1 mmol/l of BHB level was estimated as a border between hyper- (>1 mmol/l) and normal ketonaemic (<1 mmol/l) conditions. 5 different ketone patterns were distinguished: (1) non-ketotic (n=98; normal ketonaemia in all samples), (2) early type ketosis (n=45; hyperketonemia was detected only in the first week after calving), (3) late type (lacta-tional) ketosis (n=11; after a normal ketonaemic period increasing hyperketonaemia was detected in the 5th, or in the 4th and 5th weeks), (4) temporary ketosis (n=ll; hyperketonaemia was detected for 1-2 weeks in the 2nd and 3rd or in the 3rd and 4th weeks); (5) long-lasting ketosis (n=34; hyperketonaemia had been detected since calving for 4 to 5 weeks or until death or emergency slaughtering). Simultaneously with the hyperketonaemic stage increased NEFA, ACAC, depressed TCh, glucose and decreased insulin, IGF-1, T4 and T3 concentrations were detected in almost all the cases. Obvious metabolic and endocrine alterations were found, however, only in long-lasting ketosis. The TRH-stimulated T4 and T3 responses remained almost unaffected proving intact thyroid function in early and late type as well as in temporary ketosis. Depressed thyroid response and delayed onset of cyclic ovarian function were detected only in cases of long-lasting ketosis. The cows characterized by lower than normal (< mean-SD of non-ketotic cows) ACTH-stimulated cortisol response on days 1-3 after calving showed poorer chancefor spontaneous recovery. There was a significant negative correlation between the IGF-1 level in the 1st week after calving and the duration of the postpartum acyclic period. In late type (lactational) ketosis the cessation of ovarian cyclicity was the most characteristic genital malfunction.

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Takagi, Y., and B. Th Björnsson. "Regulation of cartilage glycosaminoglycan synthesis in the rainbow trout, Oncorhynchus mykiss, by 3,3′,5-tri-iodo-l-thyronine and IGF-I." Journal of Endocrinology 149, no. 2 (May 1996): 357–65. http://dx.doi.org/10.1677/joe.0.1490357.

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Abstract The actions of 3,3′,5-tri-iodo-l-thyronine (T3) and recombinant human IGF-I (rhIGF-I) as well as their interaction on cartilage growth in rainbow trout (Oncorhynchus mykiss) were examined. Uptake of 3H-methyl thymidine and 35S-sulfate by isolated branchial cartilage was measured as a marker for chondrocyte proliferation and sulfated glycosaminoglycan synthesis respectively. When T3 (1·0 μg/g) was injected intraperitoneally, plasma T3 levels reached a transient peak after 1 day and decreased rapidly thereafter. Sulfate and thymidine uptake were not affected by T3 at 1 and 3 days post-injection, but at 6 days post-injection both were significantly higher in T3injected fish than those in controls. The stimulatory effects of a T3 injection on sulfate and thymidine uptake were dose-dependent over the range of 0·01, 0·1 and 1·0 μg/g. In vitro exposure of cartilage to T3 (0·075, 0·75, 7·5, 75 and 750 nm) for 6 days resulted in dose-dependent stimulation of sulfate uptake, with a maximum response at 7·5 nm and higher. T3 exposure (7·5 nm) for 2 or 3 days also increased sulfate uptake, but only slightly. Thymidine uptake was not clearly affected by T3. In vitro addition of rhIGF-I (0·075, 0·75 and 7·5 nm) increased sulfate uptake, but not thymidine uptake, dose-dependently. Compared with T3, rhIGF-I induced a greater maximum level of sulfate uptake: at 7·5 nm rhIGF-I increased the uptake 17-fold whereas T3 increased the uptake fourfold. When T3 (0·075, 0·75 or 7·5 nm) and rhIGF-I (0·1 or 1·0 nm) were added together, stimulative actions of T3 on sulfate uptake were largely additive to those of rhIGF-I. The results indicate that T3 as well as IGF-I are important modulators of sulfated glycosaminoglycan synthesis in rainbow trout cartilage. Journal of Endocrinology (1996) 149, 357–365

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Cohen, Keren, Uri Abadi, Aleck Hercbergs, Paul J. Davis, Martin Ellis, and Osnat Ashur-Fabian. "The induction of myeloma cell death and DNA damage by tetrac, a thyroid hormone derivative." Endocrine-Related Cancer 25, no. 1 (January 2018): 21–34. http://dx.doi.org/10.1530/erc-17-0246.

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Multiple myeloma (MM) is a plasma cell malignancy in which involvement of the thyroid hormone-integrin αvβ3 pathway was shown, and pharmacologic inhibition of this pathway is a rational approach to disease management. A thyroid hormone derivative, tetraiodothyroacetic acid (tetrac), which inhibitsl-thyroxine (T4) and 3,5,3′-triiodo-l-thyronine (T3) binding to αvβ3 integrin, was studied in five MM cell lines and primary bone marrow (BM) MM cells. Tetrac inhibited MM cell proliferation (absolute cell number/viability) and induced caspase-dependent apoptosis (annexin-V/PI and cell cycle). Activation of caspase-9 and caspase-3 was further demonstrated. Moreover, DNA damage markers, ataxia-telangiectasia-mutated (ATM) kinase, poly ADP-ribose polymerase (PARP-1) and histone γH2AX were induced by tetrac. The various tetrac-initiated effects were attenuated by Arg-Gly-Asp (RGD) peptide, suggesting integrin involvement. Primary BM mononuclear cells were harvested from MM patients (n = 39) at various disease stages. Tetrac-induced apoptosis (12/17 samples) and sensitized the cytotoxic action of bortezomib (6/9 samples). Lastly, expression of plasma membrane integrin αvβ3 was shown not only in the malignant plasma clone, but also in other cell populations within the BM samples (n = 25). Tetrac is anti-proliferative and pro-apoptotic in MM and cells may offer a therapeutic approach for this disease.

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Incerpi, Sandra, Meng-Ti Hsieh, Hung-Yun Lin, Guei-Yun Cheng, Paolo De Vito, Anna Maria Fiore, R. G. Ahmed, et al. "Thyroid hormone inhibition in L6 myoblasts of IGF-I-mediated glucose uptake and proliferation: new roles for integrin αvβ3." American Journal of Physiology-Cell Physiology 307, no. 2 (July 15, 2014): C150—C161. http://dx.doi.org/10.1152/ajpcell.00308.2013.

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Thyroid hormones l-thyroxine (T4) and 3,3′,5-triiodo-l-thyronine (T3) have been shown to initiate short- and long-term effects via a plasma membrane receptor site located on integrin αvβ3. Also insulin-like growth factor type I (IGF-I) activity is known to be subject to regulation by this integrin. To investigate the possible cross-talk between T4and IGF-I in rat L6 myoblasts, we have examined integrin αvβ3-mediated modulatory actions of T4on glucose uptake, measured through carrier-mediated 2-deoxy-[3H]-d-glucose uptake, and on cell proliferation stimulated by IGF-I, assessed by cell counting, [3H]-thymidine incorporation, and fluorescence-activated cell sorting analysis. IGF-I stimulated glucose transport and cell proliferation via the cell surface IGF-I receptor (IGFIR) and, downstream of the receptor, by the phosphatidylinositol 3-kinase signal transduction pathway. Addition of 0.1 nM free T4caused little or no cell proliferation but prevented both glucose uptake and proliferative actions of IGF-I. These actions of T4were mediated by an Arg-Gly-Asp (RGD)-sensitive pathway, suggesting the existence of crosstalk between IGFIR and the T4receptor located near the RGD recognition site on the integrin. An RGD-sequence-containing integrin inhibitor, a monoclonal antibody to αvβ3, and the T4metabolite tetraiodothyroacetic acid all blocked the inhibition by T4of IGF-I-stimulated glucose uptake and cell proliferation. Western blotting confirmed roles for activated phosphatidylinositol 3-kinase and extracellular regulated kinase 1/2 (ERK1/2) in the effects of IGF-I and also showed a role for ERK1/2 in the actions of T4that modified the effects of IGF-I. We conclude that thyroid hormone inhibits IGF-I-stimulated glucose uptake and cell proliferation in L6 myoblasts.

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Raccurt, Mireille, Fannie Baudimont, Julien Tirard, Benjamin Rey, Elodie Moureaux, Alain Géloën, and Claude Duchamp. "Growing in Antarctica, a challenge for white adipose tissue development in Adélie penguin chicks (Pygoscelis adeliae)." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 295, no. 5 (November 2008): R1671—R1679. http://dx.doi.org/10.1152/ajpregu.90371.2008.

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Rapid growth is of crucial importance for Adélie penguin chicks reared during the short Antarctic summer. It partly depends on the rapid ontogenesis of fat stores that are virtually null at hatching but then develop considerably (×40) within a month to constitute both an isolative layer against cold and an energy store to fuel thermogenic and growth processes. The present study was aimed at identifying by RT-PCR the major transcriptional events that chronologically underlie the morphological transformation of adipocyte precursors into mature adipocytes from hatching to 30 days of age. The peak expression of GATA binding protein 3, a marker of preadipocytes, at day 7 posthatch indicates a key proliferation step, possibly in relation to the expression of C/EBPα (C/EBPα). High plasma total 3,5,3′-triiodo-l-thyronine (T3) levels and high levels of growth hormone receptor transcripts at hatching suggested that growth hormone and T3 play early activating roles to favor proliferation of preadipocyte precursors. Differentiation and growth of preadipocytes may occur around day 15 in connection with increased abundance of transcripts encoding IGF-1, proliferator-activated receptor-γ, and C/EBPβ, gradually leading to functional maturation of metabolic features of adipocytes including lipid uptake and storage (lipoprotein lipase, fatty-acid synthase) and late endocrine functions (adiponectin) by day 30. Present results show a close correlation between adipose tissue development and chick biology and a difference in the scheduled expression of regulatory factors controlling adipogenesis compared with in vitro studies using cell lines emphasizing the importance of in vivo approaches.

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Davis, Paul J., Shaker A. Mousa, and Hung-Yun Lin. "Nongenomic Actions of Thyroid Hormone: The Integrin Component." Physiological Reviews 101, no. 1 (January 1, 2021): 319–52. http://dx.doi.org/10.1152/physrev.00038.2019.

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The extracellular domain of plasma membrane integrin αvβ3 contains a cell surface receptor for thyroid hormone analogues. The receptor is largely expressed and activated in tumor cells and rapidly dividing endothelial cells. The principal ligand for this receptor is l-thyroxine (T4), usually regarded only as a prohormone for 3,5,3′-triiodo-l-thyronine (T3), the hormone analogue that expresses thyroid hormone in the cell nucleus via nuclear receptors that are unrelated structurally to integrin αvβ3. At the integrin receptor for thyroid hormone, T4 regulates cancer and endothelial cell division, tumor cell defense pathways (such as anti-apoptosis), and angiogenesis and supports metastasis, radioresistance, and chemoresistance. The molecular mechanisms involve signal transduction via mitogen-activated protein kinase and phosphatidylinositol 3-kinase, differential expression of multiple genes related to the listed cell processes, and regulation of activities of other cell surface proteins, such as vascular growth factor receptors. Tetraiodothyroacetic acid (tetrac) is derived from T4 and competes with binding of T4 to the integrin. In the absence of T4, tetrac and chemically modified tetrac also have anticancer effects that culminate in altered gene transcription. Tumor xenografts are arrested by unmodified and chemically modified tetrac. The receptor requires further characterization in terms of contributions to nonmalignant cells, such as platelets and phagocytes. The integrin αvβ3 receptor for thyroid hormone offers a large panel of cellular actions that are relevant to cancer biology and that may be regulated by tetrac derivatives.

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Takeda, T., K. Ichikawa, M. Kobayashi, T. Miyamoto, S. Suzuki, Y. Nishii, A. Sakurai, et al. "Response of hepatic proteins to 3,5,3′-tri-iodo-l-thyronine in diabetic rats." Journal of Endocrinology 143, no. 1 (October 1994): 55–63. http://dx.doi.org/10.1677/joe.0.1430055.

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Abstract In order to study whether peripheral action of thyroid hormones is altered in insulin deficiency and to elucidate the biological consequences of alteration of the cytosolic 3,5,3′-tri-iodo-l-thyronine (T3) binding protein (CTBP), we measured malic enzyme, T3-responsive nuclear n protein, CTBP and nuclear thyroid hormone receptor in the liver and kidney of streptozotocin (STZ)-induced diabetic rats that were treated with or without insulin and/or a receptor-saturating dose of T3. The following results were obtained. 1. Induction of malic enzyme by T3 was apparently diminished in diabetic rats. However, supplementary injection of insulin enabled previously given T3 to take effect in diabetic rats. 2. T3-responsiveness of other hepatic proteins (n protein and CTBP) was not altered by insulin in diabetic rats. 3. The level of n protein was increased by insulin in diabetic rats in vivo and in perfused rat liver, indicating that the hepatic n protein is a novel insulin-responsive protein. T3 and insulin increased the level of n protein non-synergistically in diabetic rat liver. 4. Hepatic nuclear receptor levels were not altered in diabetic rats. 5. Hepatic CTBP levels were decreased in diabetic rats. This was not due to the toxic effect of STZ. Low CTBP level was only partially increased by insulin after 30 days of diabetic period. Renal CTBP levels were not altered in diabetic rats with or without insulin treatment. These results indicate that reduction of CTBP did not influence the hepatic response to a receptor-saturating dose of T3, although CTBP may regulate the nuclear T3 transport, and that fundamental action of a receptor-saturating dose of T3 was not attenuated in diabetic rat liver. Journal of Endocrinology (1994) 143, 55–63

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Segal, J., S. Masalha, H. Schwalb, G. Merin, J. B. Borman, and G. Uretzky. "Acute effect of thyroid hormone in the rat heart: role of calcium." Journal of Endocrinology 149, no. 1 (April 1996): 73–80. http://dx.doi.org/10.1677/joe.0.1490073.

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Abstract Several observations provide some clues as to the possible mode of the regulatory action of thyroid hormone (TH) in the heart, indicating delayed action at the level of the nucleus and acute effects on the plasma membrane. Here we present evidence for a direct and rapid stimulatory effect of TH in the intact normal heart. In the isolated perfused rat heart, 3,5,3′-tri-iodothyronine (T3) produced a positive inotropic effect increasing both the left ventricular peak systolic pressure (P) and +dP/dt values, but had no significant effect on heart rate. This effect of T3 was: (1) very rapid in onset (starting after 15 s) and transient, increasing gradually to reach a maximum (80% above control) at about 20 min, and declining progressively 20 to 30 min later; (2) dose-related and biphasic, occurring at physiological concentrations as low as 1 pm (+dP/dt) and 10 pm (P), reaching a maximum at 1 nm, and decreasing at higher concentrations; and (3) thyroid hormone specific, as shown by the effects of several TH analogs (l-T3>l-thyroxine (T4)=d-T3>d-T4; 3,3′,5′-tri-iodothyronine (rT3), 3,5,-l-di-iodothyronine and dl-thyronine had no effect). The calcium blockers nifedipine and verapamil, at concentrations of 10−8–10−5 m given before or after the addition of T3 (10−9–10−6 m), inhibited the T3-induced increase in cardiac inotropic activity in a time- and dose-related fashion. We suggest that the acute effect of TH in the heart is plasma membrane-mediated and calcium-dependent. Journal of Endocrinology (1996) 149, 73–80

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35

Schmitt, Roland, Enno Klussmann, Thomas Kahl, David H. Ellison, and Sebastian Bachmann. "Renal expression of sodium transporters and aquaporin-2 in hypothyroid rats." American Journal of Physiology-Renal Physiology 284, no. 5 (May 1, 2003): F1097—F1104. http://dx.doi.org/10.1152/ajprenal.00368.2002.

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Hypothyroidism is associated with significant abnormalities in the renal handling of salt and water. To address the involvement of tubular transport proteins in these abnormalities, rats were rendered pharmacologically hypothyroid and the abundance of major tubular transport proteins was assessed by immunoblot and immunohistochemistry. Hypothyroidism resulted in a marked reduction in kidney size and creatinine clearance along with decreased or unchanged total kidney abundance of the transport proteins. Whereas the proximal tubular type 3 Na/H exchanger (NHE3) and type 2 Na-phosphate cotransporter (NaPi2) stood out by their disproportionately reduced abundance, the bumetanide-sensitive type 2 Na-K-2Cl cotransporter (NKCC2) and aquaporin-2 (AQP2) were unaltered in their total kidney abundance despite a markedly lower kidney mass. The latter proteins in fact showed enhanced immunostaining. Decreased NHE3 and NaPi2 expression was most likely due to a combination of triiodo-l-thyronine (T3) deficiency along with a reduced glomerular filtration rate. The increased abundance of NKCC2 and AQP2 may have been caused by an increased action of vasopressin since urinary excretion of this hormone was elevated. On the other hand, the thiazide-sensitive Na-Cl cotransporter; the α-, β-, and γ-subunits of the amiloride-sensitive epithelial Na channel; and the α1-subunit of Na-K-ATPase showed a moderate decrease in total kidney abundance that was largely proportional to the smaller kidney mass. Although the observed expression of transporters was associated with a balanced renal sodium handling, altered transporter abundance may become functionally relevant if the hypothyroid kidney is challenged by an additional destabilization of the milieu interieur that has previously been shown to result in an inadequate natriuresis and clinical symptoms.

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36

Lee, C. G. L., and Y. K. Ip. "Environmental effect on plasma thyroxine (t4), 3,5,3'-triido-l-thyronine (t3), prolactin and cyclic adenosine 3',5'-monophosphate (camp) content in the mudskippers Periophthalmus Chrysospilos and Boleophthalmus Boddaerti." Comparative Biochemistry and Physiology Part A: Physiology 87, no. 4 (January 1987): 1009–14. http://dx.doi.org/10.1016/0300-9629(87)90028-4.

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37

Jongejan, Rutchanna M. S., Theo Klein, Marcel E. Meima, W. Edward Visser, Ramona E. A. van Heerebeek, Theo M. Luider, Robin P. Peeters, and Yolanda B. de Rijke. "A Mass Spectrometry-Based Panel of Nine Thyroid Hormone Metabolites in Human Serum." Clinical Chemistry 66, no. 4 (February 11, 2020): 556–66. http://dx.doi.org/10.1093/clinchem/hvaa022.

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Abstract Background While thyroxine (T4), 3,3’,5-triiodothyronine (T3), and 3,3’,5’-triiodothyronine (rT3) have routine methods available for evaluating patients with suspected thyroid disease, appropriate methods for the measurement of other thyroid hormone metabolites (THMs) are lacking. The effects of other iodothyronines or iodothyroacetic acids are therefore less explored. To better understand the (patho)physiological role of THMs, a robust method to measure iodothyronines and iodothyroacetic acids in serum in a single analysis is needed, including associated reference intervals. Methods Clinical and Laboratory Standards Institute guidelines, European Medicines Agency guidelines, and the National Institute of Standards and Technology protocol were used for the method validation and reference intervals. Reference intervals were determined in 132 healthy males and 121 healthy females. Serum samples were deproteinized with acetonitrile, followed by anion-exchange solid phase extraction and analysis with LC-MS/MS, using eight 13C6-internal standards Results The analytical method validation was performed for all nine THMs. Reference intervals (2.5th to 97.5th percentile) were determined for L-thyronine (4.9–11.3 ng/dL), 3-monoiodothyronine (0.06 --0.41 ng/dL), 3,5-diiodothyronine (<0.13 ng/dL), 3,3’-diiodothyronine (0.25--0.77 ng/dL), T3 (66.4--129.9 ng/dL), rT3 (15.0--64.1 ng/dL), T4 (4.3--10.0 µg/dL), triac/3,3’,5-triiodothyroacetic acid (not detected), and tetrac/3,3’,5,5’-tetraiodothyroacetic acid (2.2--27.2 ng/dL). Conclusions A broad dynamic concentration range exists among the nine THMs. This method should help to develop a better understanding of the clinical relevance of other THMs, as well as an understanding of thyroid hormone metabolism in health and disease.

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Walker, Jennifer D., Fred A. Crawford, Rupak Mukherjee, Michael R. Zile, and Francis G. Spinale. "Direct effects of acute administration of 3, 5, 3′ triiodo-l-thyronine on myocyte function." Annals of Thoracic Surgery 58, no. 3 (September 1994): 851–56. http://dx.doi.org/10.1016/0003-4975(94)90766-8.

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Wang, Xue, S. O. Adeniran, Ziming Wang, Xiaoyu Li, Fushuo Huang, Mingjun Ma, Zhongfeng Xu, Peng Zheng, and Guixue Zhang. "3, 3′, 5-Triiodo-L-thyronine affects polarity proteins of bovine Sertoli cells via WT1/non-canonical Wnt signaling pathway." Theriogenology 148 (May 2020): 8–17. http://dx.doi.org/10.1016/j.theriogenology.2020.02.034.

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40

Hasumura, Satoshi, Shuji Kitagawa, Ira Pastan, and Sheue-yann Cheng. "Solubilization and characterization of a membrane 3, 3′, 5-triiodo-L-thyronine binding protein from rat pituitary tumor GH3 cells." Biochemical and Biophysical Research Communications 133, no. 3 (December 1985): 837–43. http://dx.doi.org/10.1016/0006-291x(85)91210-0.

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Fernández-Pernas, Pablo, Juan Fafián-Labora, Iván Lesende-Rodriguez, Jesús Mateos, Alexandre De la Fuente, Isaac Fuentes, Javier De Toro Santos, Fco Blanco García, and María C. Arufe. "3, 3′, 5-triiodo-L-thyronine Increases In Vitro Chondrogenesis of Mesenchymal Stem Cells From Human Umbilical Cord Stroma Through SRC2." Journal of Cellular Biochemistry 117, no. 9 (March 30, 2016): 2097–108. http://dx.doi.org/10.1002/jcb.25515.

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42

Sar, Pranati, Rosalima Peter, Bandita Rath, Alok Das Mohapatra, and Sandip K. Mishra. "3, 3′5 Triiodo L Thyronine Induces Apoptosis in Human Breast Cancer MCF-7cells, Repressing SMP30 Expression through Negative Thyroid Response Elements." PLoS ONE 6, no. 6 (June 7, 2011): e20861. http://dx.doi.org/10.1371/journal.pone.0020861.

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43

Poczyczynski, Pawel, Andrzej Mamcarz, and Jacek Kozlowski. "Effect of different levels of 3, 5, 3’-triiodo-L-thyronine Administration in a dry diet on rearing of Whitefish (Coregonus lavaretus L., Coregoninae) Larvae." Madridge Journal of Aquaculture Research & Development 1, no. 1 (November 27, 2017): 31–34. http://dx.doi.org/10.18689/mjard-1000106.

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Chakrabarti, Nilkanta, and Arun K. Ray. "Stimulation of AChE activity in relation to changes in electronmicroscopic structure of adult rat cerebrocortical synaptosomes pretreated with 3-5-3'-triiodo-L-thyronine." NeuroReport 14, no. 11 (August 2003): 1497–501. http://dx.doi.org/10.1097/00001756-200308060-00019.

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45

Morin, P. P., T. J. Hara, and J. G. Eales. "Thyroid function and olfactory responses to L-alanine during induced smoltification in Atlantic salmon, Salmo salar." Canadian Journal of Fisheries and Aquatic Sciences 54, no. 3 (March 1, 1997): 596–602. http://dx.doi.org/10.1139/f96-309.

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For 5 weeks starting in mid-February we examined developmental correlations between external smolt features, plasma thyroid hormone levels, and olfactory responses in Atlantic salmon transferred from 0.9 to 11°C and exposed to a 16 h light : 8 h dark (16L) or an 8 h light : 16 h dark (8L) photoperiod. In 16L fish, external smolt features developed to 80% of full state, plasma L-thyroxine (T4) surged at week 3, but there were no changes in plasma 3,5,3 prime -triiodo-L-thyronine, olfactory bulb electroencephalographic (EEG), or olfactory epithelium electro-olfactographic (EOG) activities in response to nasal stimulation with L-alanine (10-9 to 10-5 M). In 8L fish, external smolt features were arrested at 40% of full state, plasma T4 showed no surge, EOG activity increased modestly, but EEG activity increased markedly at weeks 3 and 4. Thus, under the particular photoperiod and temperature conditions imposed in this study in February and March, enhanced olfactory activity can develop in premigratory Atlantic salmon independently of external smolt features or a significant surge in plasma T4.

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46

Iwase, Katsumi, Brian C. W. Hummel, and Paul G. Walfish. "Cytosol components from human placenta and rat liver in iodothyronine 5- and 5′-deiodination." Biochemistry and Cell Biology 67, no. 1 (January 1, 1989): 58–63. http://dx.doi.org/10.1139/o89-009.

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Using either human placental microsomal 5-deiodinase as enzyme (5-DI) and thyroxine as substrate or rat liver (RL) microsomal 5′-deiodinase (5′ DI) as enzyme and reverse [(3′- or 5′-)-125I]triiodo-L-thyronine ([125I]rT3) as substrate, activation of 5′-DI in the presence of NADPH was observed using either human placental or rat liver cytosolic components, but there was no activation of 5-DI. Both could be activated by DTT, with higher concentrations being required for 5-DI than for 5′-DI. Iopanoic acid, dicumarol, and sodium arsenite inhibited 5′-DI and 5-DI activated by DTT. In the presence of DTT, 1 mM 6-propyl-2-thiouracil had no effect on 5-DI but inhibited 5′ DI. Thus, human placental and rat liver cytosolic components are interchangeable in activating hepatic 5′-DI in the presence of NADPH. However, if an endogenous cofactor system involved in the activation of human placental 5-DI exists, it probably differs from the activator of liver 5′-DI.Key words: iodothyronines, deiodination cofactors, placenta, liver, cytosol.

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Vargas, Miguel A., Miguel Cisneros, Patricia Joseph-Bravo, and Jean-Louis Charli. "Regulation of Adenohypophyseal Pyroglutamyl Aminopeptidase II Activity by Thyrotropin-Releasing Hormone and Phorbol Esters: Dependence on 3,3',5'-Triiodo-L-Thyronine and Gender." Endocrine 13, no. 3 (2000): 267–72. http://dx.doi.org/10.1385/endo:13:3:267.

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Schneider, JJ, and DA Hood. "Effect of thyroid hormone on mtHsp70 expression, mitochondrial import and processing in cardiac muscle." Journal of Endocrinology 165, no. 1 (April 1, 2000): 9–17. http://dx.doi.org/10.1677/joe.0.1650009.

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Mitochondrial heat shock protein 70 (mtHsp70), an important mitochondrial chaperone, is increased in cardiac muscle mitochondria of hyperthyroid rats. To determine the mechanism(s) underlying this increase, we used variations in thyroid status. In Series I, rats were made hyperthyroid by injecting them with 3,3', 5-triiodo-l-thyronine (T(3)) for 5 days, or by treating them with vehicle. In Series II, animals were given 6-n-propyl-2-thiouracil in their drinking water (0.05% w/v) for a period of 32-42 days to make them hypothyroid. During the last 5 days of treatment these animals received injections of either T(3) or vehicle. T(3) treatment resulted in parallel increases in mtHsp70 protein and mRNA levels in a variety of tissues, suggesting transcriptional regulation. However, evidence of tissue-specific post-transcriptional regulation was also apparent. In isolated heart mitochondria, T(3) treatment resulted in a 1.8-fold increase in mtHsp70. This was due to the 1. 6-fold greater import of mtHsp70 into mitochondria in T(3), compared with hypothyroid animals, and it could not be attributed to an altered rate of intramitochondrial mtHsp70 degradation. The rate of processing of mtHsp70 to its mature form, reflecting mitochondrial processing peptidase activity, was unaffected by T(3), but was more rapid than mtHsp70 import. These data indicate a novel mechanism by which T(3) modifies the mitochondrial phenotype via the adaptations in the protein import pathway.

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Degens, H., A. J. Gilde, M. Lindhout, P. H. M. Willemsen, G. J. van der Vusse, and M. van Bilsen. "Functional and metabolic adaptation of the heart to prolonged thyroid hormone treatment." American Journal of Physiology-Heart and Circulatory Physiology 284, no. 1 (January 1, 2003): H108—H115. http://dx.doi.org/10.1152/ajpheart.00282.2002.

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In heart failure, thyroid hormone (TH) treatment improves cardiac performance. The long-term effects of TH on cardiac function and metabolism, however, are incompletely known. To investigate the effects of up to 28 days of TH treatment, male Wistar rats received 3,3′,5-triiodo-l-thyronine (200 μg/kg sc per day) leading to a 2.5-fold rise in plasma fatty acid (FA) level and progressive cardiac hypertrophy (+47% after 28 days) ( P < 0.001). Ejection fraction (echocardiography) was increased (+12%; P < 0.05) between 7 and 14 days and declined thereafter. Neither cardiac FA oxidation, glycolytic capacity (homogenates) per unit muscle mass, nor mRNA levels of proteins involved in FA and glucose uptake and metabolism (Northern blots and microarray) were altered. After 28 days of treatment, mRNA levels of uncoupling proteins (UCP) 2 and 3 and atrial natriuretic factor were increased ( P < 0.05). This indicates that TH-induced hypertrophy is associated with an initial increase in cardiac performance, followed by a decline in cardiac function and increased expression of UCPs and atrial natriuretic factor, suggesting that detrimental effects eventually prevail.

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Takada, Makoto, Hideko Yai, and Shinji Komazaki. "Effect of calcium on development of amiloride-blockable Na+ transport in axolotl in vitro." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 275, no. 1 (July 1, 1998): R69—R75. http://dx.doi.org/10.1152/ajpregu.1998.275.1.r69.

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The axolotl, Ambystoma mexicanum, which has no specific calcium-containing sieve layer in the dermis, provides useful material for the study of the effect of Ca2+ on the development of amiloride-blockable active Na+ transport across the skin of amphibians. We raised axolotls in thyroid hormone or aldosterone or cultured the skin with corticoid plus one of several Ca2+ concentrations and found that 1) although the short-circuit current (SCC) was increased by both aldosterone and 3,3′,5-triiodo-l-thyronine in vivo, only corticoid was necessary for such an increase in vitro; 2) the development of the SCC in vitro was both corticoid and Ca2+dependent, because the SCC was well developed with over 100 μM Ca2+ but not with under 10 μM Ca2+ in the presence of corticoid, nor even with 300 μM Ca2+without corticoid; and 3) Ca2+, but not corticoid, was necessary for the formation of cell-to-cell junctions, because the resistance of the skin was well developed with 300 μM Ca2+ without corticoid.

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Journal articles on the topic '3, 3', 5-triiodo-l-thyronine(t3)'

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