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Zhang H, Huang H, Zheng P, Feng R, Wang X, Huang F, Ma M, Tian Y, Zhang G. The alleviative effect of thyroid hormone on cold stress-induced apotosis via HSP70 and mitochondrial apoptosis signal pathway in bovine Sertoli cells. Cryobiology 2021; 105:63-70. [PMID: 34863702 DOI: 10.1016/j.cryobiol.2021.11.181] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Revised: 11/29/2021] [Accepted: 11/30/2021] [Indexed: 11/17/2022]
Abstract
Thyroid hormone was involved in gene expression and functional regulation in various signal pathways. Cold stress can increase triiodothyronine (T3) level in the blood. The aim of this study was to investigate the effect of T3 on HSP70 expression and apoptosis in Sertoli cells (SCs) under cold stress in vitro culture at 26 °C, and provide a theoretical and practical basis for improving the reproductive efficiency of bulls in cold areas. SCs were treated with different cold stress duration and different T3 concentrations for pre-screening. HSP70 inhibitor was added later, and the apoptotic rate was measured using flow cytometry. The expression of HSP70 and the main genes of mitochondrial apoptosis pathway were determined by means of real-time PCR and western-blot, respectively. The localization of HSP70 was assessed by immunofluorescence. The results showed that cold stress (26 °C, 6 h) played an inductive role in SCs apoptotic rate (P < 0.01) and the transfer of HSP70 into the nucleus. 100 nM T3 further promoted HSP70 expression and its transfer into the nucleus, which significantly inhibited the expression of vital genes (cyt-c, Caspase-9 and Caspase-3) in mitochondrial pathway (P < 0.05). Subsequently, higher survival and lower apoptotic rates of SCs (P < 0.01) were observed. When T3 and HSP70 inhibitor were added together, the expression of cyt-c, Caspase-9 and Caspase-3 were inhibited (P < 0.05), and then the declining apoptotic rate increased again (P < 0.01). In conclusion, T3 can regulate HSP70 expression and translocation to mediate mitochondrial apoptosis pathway to inhibit SCs apoptosis induced by cold stress.
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Affiliation(s)
- Han Zhang
- College of Animal Science and Technology, Northeast Agricultural University, Harbin, 150030, People's Republic of China
| | - He Huang
- College of Animal Science and Technology, Northeast Agricultural University, Harbin, 150030, People's Republic of China
| | - Peng Zheng
- College of Animal Science and Technology, Northeast Agricultural University, Harbin, 150030, People's Republic of China
| | - Rui Feng
- College of Animal Science and Technology, Northeast Agricultural University, Harbin, 150030, People's Republic of China
| | - Xue Wang
- College of Animal Science and Technology, Northeast Agricultural University, Harbin, 150030, People's Republic of China
| | - Fushuo Huang
- College of Animal Science and Technology, Northeast Agricultural University, Harbin, 150030, People's Republic of China
| | - Mingjun Ma
- College of Animal Science and Technology, Northeast Agricultural University, Harbin, 150030, People's Republic of China
| | - Yaguang Tian
- College of Animal Science and Technology, Northeast Agricultural University, Harbin, 150030, People's Republic of China
| | - Guixue Zhang
- College of Animal Science and Technology, Northeast Agricultural University, Harbin, 150030, People's Republic of China.
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Cote-Vélez A, Martínez Báez A, Lezama L, Uribe RM, Joseph-Bravo P, Charli JL. A screen for modulators reveals that orexin-A rapidly stimulates thyrotropin releasing hormone expression and release in hypothalamic cell culture. Neuropeptides 2017; 62:11-20. [PMID: 28173961 DOI: 10.1016/j.npep.2017.01.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/18/2016] [Revised: 01/25/2017] [Accepted: 01/30/2017] [Indexed: 12/21/2022]
Abstract
In the paraventricular nucleus of the mammalian hypothalamus, hypophysiotropic thyrotropin releasing hormone (TRH) neurons integrate metabolic information and control the activity of the thyroid axis. Additional populations of TRH neurons reside in various hypothalamic areas, with poorly defined connections and functions, albeit there is evidence that some may be related to energy balance. To establish extracellular modulators of TRH hypothalamic neurons activity, we performed a screen of neurotransmitters effects in hypothalamic cultures. Cell culture conditions were chosen to facilitate the full differentiation of the TRH neurons; these conditions had permitted the characterization of the effects of known modulators of hypophysiotropic TRH neurons. The major end-point of the screen was Trh mRNA levels, since they are generally rapidly (0.5-3h) modified by synaptic inputs onto TRH neurons; in some experiments, TRH cell content or release was also analyzed. Various modulators, including histamine, serotonin, β-endorphin, met-enkephalin, and melanin concentrating hormone, had no effect. Glutamate, as well as ionotropic agonists (kainate and N-Methyl-d-aspartic acid), increased Trh mRNA levels. Baclofen, a GABAB receptor agonist, and dopamine enhanced Trh mRNA levels. An endocannabinoid receptor 1 inverse agonist promoted TRH release. Somatostatin increased Trh mRNA levels and TRH cell content. Orexin-A rapidly increased Trh mRNA levels, TRH cell content and release, while orexin-B decreased Trh mRNA levels. These data reveal unaccounted regulators, which exert potent effects on hypothalamic TRH neurons in vitro.
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Affiliation(s)
- Antonieta Cote-Vélez
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México (UNAM), Cuernavaca, Mor. 62271, Mexico
| | - Anabel Martínez Báez
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México (UNAM), Cuernavaca, Mor. 62271, Mexico
| | - Leticia Lezama
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México (UNAM), Cuernavaca, Mor. 62271, Mexico
| | - Rosa María Uribe
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México (UNAM), Cuernavaca, Mor. 62271, Mexico
| | - Patricia Joseph-Bravo
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México (UNAM), Cuernavaca, Mor. 62271, Mexico
| | - Jean-Louis Charli
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México (UNAM), Cuernavaca, Mor. 62271, Mexico.
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Joseph-Bravo P, Jaimes-Hoy L, Uribe RM, Charli JL. 60 YEARS OF NEUROENDOCRINOLOGY: TRH, the first hypophysiotropic releasing hormone isolated: control of the pituitary-thyroid axis. J Endocrinol 2015; 226:T85-T100. [PMID: 26101376 DOI: 10.1530/joe-15-0124] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 06/22/2015] [Indexed: 12/25/2022]
Abstract
This review presents the findings that led to the discovery of TRH and the understanding of the central mechanisms which control hypothalamus-pituitary-thyroid axis (HPT) activity. The earliest studies on thyroid physiology are now dated a century ago when basal metabolic rate was associated with thyroid status. It took over 50 years to identify the key elements involved in the HPT axis. Thyroid hormones (TH: T4 and T3) were characterized first, followed by the semi-purification of TSH whose later characterization paralleled that of TRH. Studies on the effects of TH became possible with the availability of synthetic hormones. DNA recombinant techniques facilitated the identification of all the elements involved in the HPT axis, including their mode of regulation. Hypophysiotropic TRH neurons, which control the pituitary-thyroid axis, were identified among other hypothalamic neurons which express TRH. Three different deiodinases were recognized in various tissues, as well as their involvement in cell-specific modulation of T3 concentration. The role of tanycytes in setting TRH levels due to the activity of deiodinase type 2 and the TRH-degrading ectoenzyme was unraveled. TH-feedback effects occur at different levels, including TRH and TSH synthesis and release, deiodinase activity, pituitary TRH-receptor and TRH degradation. The activity of TRH neurons is regulated by nutritional status through neurons of the arcuate nucleus, which sense metabolic signals such as circulating leptin levels. Trh expression and the HPT axis are activated by energy demanding situations, such as cold and exercise, whereas it is inhibited by negative energy balance situations such as fasting, inflammation or chronic stress. New approaches are being used to understand the activity of TRHergic neurons within metabolic circuits.
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Affiliation(s)
- Patricia Joseph-Bravo
- Departamento de Genética del Desarrollo y Fisiología MolecularInstituto de Biotecnología, Universidad Nacional Autónoma de México (UNAM), A.P. 510-3, Cuernavaca, Morelos 62250, Mexico
| | - Lorraine Jaimes-Hoy
- Departamento de Genética del Desarrollo y Fisiología MolecularInstituto de Biotecnología, Universidad Nacional Autónoma de México (UNAM), A.P. 510-3, Cuernavaca, Morelos 62250, Mexico
| | - Rosa-María Uribe
- Departamento de Genética del Desarrollo y Fisiología MolecularInstituto de Biotecnología, Universidad Nacional Autónoma de México (UNAM), A.P. 510-3, Cuernavaca, Morelos 62250, Mexico
| | - Jean-Louis Charli
- Departamento de Genética del Desarrollo y Fisiología MolecularInstituto de Biotecnología, Universidad Nacional Autónoma de México (UNAM), A.P. 510-3, Cuernavaca, Morelos 62250, Mexico
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Joseph-Bravo P, Jaimes-Hoy L, Charli JL. Regulation of TRH neurons and energy homeostasis-related signals under stress. J Endocrinol 2015; 224:R139-59. [PMID: 25563352 DOI: 10.1530/joe-14-0593] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Energy homeostasis relies on a concerted response of the nervous and endocrine systems to signals evoked by intake, storage, and expenditure of fuels. Glucocorticoids (GCs) and thyroid hormones are involved in meeting immediate energy demands, thus placing the hypothalamo-pituitary-thyroid (HPT) and hypothalamo-pituitary-adrenal axes at a central interface. This review describes the mode of regulation of hypophysiotropic TRHergic neurons and the evidence supporting the concept that they act as metabolic integrators. Emphasis has been be placed on i) the effects of GCs on the modulation of transcription of Trh in vivo and in vitro, ii) the physiological and molecular mechanisms by which acute or chronic situations of stress and energy demands affect the activity of TRHergic neurons and the HPT axis, and iii) the less explored role of non-hypophysiotropic hypothalamic TRH neurons. The partial evidence gathered so far is indicative of a contrasting involvement of distinct TRH cell types, manifested through variability in cellular phenotype and physiology, including rapid responses to energy demands for thermogenesis or physical activity and nutritional status that may be modified according to stress history.
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Affiliation(s)
- Patricia Joseph-Bravo
- Departamento de Genética del Desarrollo y Fisiología MolecularInstituto de Biotecnología, Universidad Nacional Autónoma de México (UNAM), A.P. 510-3, Cuernavaca, Morelos 62250, Mexico
| | - Lorraine Jaimes-Hoy
- Departamento de Genética del Desarrollo y Fisiología MolecularInstituto de Biotecnología, Universidad Nacional Autónoma de México (UNAM), A.P. 510-3, Cuernavaca, Morelos 62250, Mexico
| | - Jean-Louis Charli
- Departamento de Genética del Desarrollo y Fisiología MolecularInstituto de Biotecnología, Universidad Nacional Autónoma de México (UNAM), A.P. 510-3, Cuernavaca, Morelos 62250, Mexico
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Sotelo-Rivera I, Jaimes-Hoy L, Cote-Vélez A, Espinoza-Ayala C, Charli JL, Joseph-Bravo P. An acute injection of corticosterone increases thyrotrophin-releasing hormone expression in the paraventricular nucleus of the hypothalamus but interferes with the rapid hypothalamus pituitary thyroid axis response to cold in male rats. J Neuroendocrinol 2014; 26:861-9. [PMID: 25283355 DOI: 10.1111/jne.12224] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2014] [Revised: 08/13/2014] [Accepted: 09/25/2014] [Indexed: 11/27/2022]
Abstract
The activity of the hypothalamic-pituitary-thyroid (HPT) axis is rapidly adjusted by energy balance alterations. Glucocorticoids can interfere with this activity, although the timing of this interaction is unknown. In vitro studies indicate that, albeit incubation with either glucocorticoid receptor (GR) agonists or protein kinase A (PKA) activators enhances pro-thyrotrophin-releasing hormone (pro-TRH) transcription, co-incubation with both stimuli reduces this enhancement. In the present study, we used primary cultures of hypothalamic cells to test whether the order of these stimuli alters the cross-talk. We observed that a simultaneous or 1-h prior (but not later) activation of GR is necessary to inhibit the stimulatory effect of PKA activation on pro-TRH expression. We tested these in vitro results in the context of a physiological stimulus on the HPT axis in adult male rats. Cold exposure for 1 h enhanced pro-TRH mRNA expression in neurones of the hypophysiotrophic and rostral subdivisions of the paraventricular nucleus (PVN) of the hypothalamus, thyrotrophin (TSH) serum levels and deiodinase 2 (D2) activity in brown adipose tissue (BAT). An i.p. injection of corticosterone stimulated pro-TRH expression in the PVN of rats kept at ambient temperature, more pronouncedly in hypophysiotrophic neurones that no longer responded to cold exposure. In corticosterone-pretreated rats, the cold-induced increase in pro-TRH expression was detected only in the rostral PVN. Corticosterone blunted the increase in serum TSH levels and D2 activity in BAT produced by cold in vehicle-injected animals. Thus, increased serum corticosterone levels rapidly restrain cold stress-induced activation of TRH hypophysiotrophic neurones, which may contribute to changing energy expenditure. Interestingly, TRH neurones of the rostral PVN responded to both corticosterone and cold exposure with an amplified expression of pro-TRH mRNA, suggesting that these neurones integrate stress and temperature distinctly from the hypophysiotrophic neurones.
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Affiliation(s)
- I Sotelo-Rivera
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México (UNAM), Cuernavaca, Morelos, México
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Ohba K, Takayama T, Matsunaga H, Matsushita A, Sasaki S, Oki Y, Ozono S, Nakamura H. Inappropriate elevation of serum thyrotropin levels in patients treated with axitinib. Thyroid 2013; 23:443-8. [PMID: 23157669 DOI: 10.1089/thy.2012.0378] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
BACKGROUND Although anticancer treatment with the tyrosine kinase inhibitor (TKI) axitinib frequently causes thyroid dysfunction, the associated mechanism and clinical features have not been elucidated. METHODS Six patients were treated with axitinib for metastatic renal cell carcinoma at the Hamamatsu University School of Medicine between 2008 and 2010. We reviewed their thyroid function results and compared them to those of patients treated with two other TKIs, sunitinib or sorafenib, and to those of subjects with normal hypothalamic-pituitary-thyroid (HPT) function. RESULTS Axitinib-induced thyroid dysfunction was observed in all patients, and two patterns were observed: increased serum thyrotropin (TSH) levels within one month after administration occurred in five patients and transient thyrotoxicosis due to destructive thyroiditis occurred in five patients within 7 months of treatment. Four patients exhibited both. When the relationship between the serum TSH and thyroid hormones was evaluated using plots of TSH versus both free thyroxine and free triiodothyronine, four patients showed an inappropriate elevation of serum TSH during administration of axitinib. Their values apparently shifted against the regression line compared to data from patients with a normal HPT function. A similar tendency, though weaker, was observed in some patients treated with sunitinib or sorafenib. CONCLUSION This is the first study to report an inappropriate elevation of serum TSH levels in patients treated with axitinib.
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Affiliation(s)
- Kenji Ohba
- Second Division, Department of Internal Medicine, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka, Japan.
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El Yamani FZ, Yon L, Guérin M, El Ouezzani S, Alaoui A, Chartrel N, Anouar Y, Magoul R. Immunocytochemical distribution of EM66 within the hypothalamic parvocellular paraventricular nucleus: Colocalization with CRH and TRH but no plasticity related to acute stress and thyroidectomy in the rat. ACTA ACUST UNITED AC 2013; 182:28-34. [DOI: 10.1016/j.regpep.2012.12.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2012] [Revised: 09/04/2012] [Accepted: 12/17/2012] [Indexed: 10/27/2022]
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Chiappini F, Ramadoss P, Vella KR, Cunha LL, Ye FD, Stuart RC, Nillni EA, Hollenberg AN. Family members CREB and CREM control thyrotropin-releasing hormone (TRH) expression in the hypothalamus. Mol Cell Endocrinol 2013; 365:84-94. [PMID: 23000398 PMCID: PMC3572472 DOI: 10.1016/j.mce.2012.09.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2012] [Revised: 09/05/2012] [Accepted: 09/11/2012] [Indexed: 01/19/2023]
Abstract
Thyrotropin-releasing hormone (TRH) in the paraventricular nucleus (PVN) of the hypothalamus is regulated by thyroid hormone (TH). cAMP response element binding protein (CREB) has also been postulated to regulate TRH expression but its interaction with TH signaling in vivo is not known. To evaluate the role of CREB in TRH regulation in vivo, we deleted CREB from PVN neurons to generate the CREB1(ΔSIM1) mouse. As previously shown, loss of CREB was compensated for by an up-regulation of CREM in euthyroid CREB1(ΔSIM1) mice but TSH, T₄ and T₃ levels were normal, even though TRH mRNA levels were elevated. Interestingly, TRH mRNA expression was also increased in the PVN of CREB1(ΔSIM1) mice in the hypothyroid state but became normal when made hyperthyroid. Importantly, CREM levels were similar in CREB1(ΔSIM1) mice regardless of thyroid status, demonstrating that the regulation of TRH by T₃ in vivo likely occurs independently of the CREB/CREM family.
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Affiliation(s)
- Franck Chiappini
- Division of Endocrinology, Diabetes and Metabolism. Beth Israel Deaconess Medical Center and Harvard Medical School. Center of Life Science, Boston, MA, 02115. ; ; ; ; ;
- Address correspondence and reprint request to: Dr. Franck Chiappini or Dr. Anthony Hollenberg, MD, 330 Brookline Avenue, E/CLS 0728, MA, 02215. Tel: 617-735-3268. Fax: 617-735-3323; ,
| | - Preeti Ramadoss
- Division of Endocrinology, Diabetes and Metabolism. Beth Israel Deaconess Medical Center and Harvard Medical School. Center of Life Science, Boston, MA, 02115. ; ; ; ; ;
| | - Kristen R. Vella
- Division of Endocrinology, Diabetes and Metabolism. Beth Israel Deaconess Medical Center and Harvard Medical School. Center of Life Science, Boston, MA, 02115. ; ; ; ; ;
| | - Lucas L. Cunha
- Division of Endocrinology, Diabetes and Metabolism. Beth Israel Deaconess Medical Center and Harvard Medical School. Center of Life Science, Boston, MA, 02115. ; ; ; ; ;
| | - Felix D. Ye
- Division of Endocrinology, Diabetes and Metabolism. Beth Israel Deaconess Medical Center and Harvard Medical School. Center of Life Science, Boston, MA, 02115. ; ; ; ; ;
| | - Ronald C. Stuart
- Division of Endocrinology, The Warren Alpert Medical School of Brown University, Rhode Island Hospital, Providence, RI 02903. ;
| | - Eduardo A. Nillni
- Division of Endocrinology, The Warren Alpert Medical School of Brown University, Rhode Island Hospital, Providence, RI 02903. ;
| | - Anthony N. Hollenberg
- Division of Endocrinology, Diabetes and Metabolism. Beth Israel Deaconess Medical Center and Harvard Medical School. Center of Life Science, Boston, MA, 02115. ; ; ; ; ;
- Address correspondence and reprint request to: Dr. Franck Chiappini or Dr. Anthony Hollenberg, MD, 330 Brookline Avenue, E/CLS 0728, MA, 02215. Tel: 617-735-3268. Fax: 617-735-3323; ,
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Yamashita K, Suganuma K, Funase Y, Yamauchi K, Aizawa T. Elevation of thyrotropin upon accidental hypothermia in an elderly man. Thyroid 2012; 22:1291-3. [PMID: 23083443 DOI: 10.1089/thy.2012.0084] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
BACKGROUND Although "polar triiodothyronine (T(3)) syndrome" in chronic dwellers/workers in Antarctica has been established, alteration of the pituitary thyroid-axis upon accidental hypothermia is not well recognized. We report here a rare case of elevation of thyrotropin (TSH) upon accidental hypothermia. PATIENT FINDINGS A 75-year-old man was admitted because of consciousness disturbance.The mean outside temperature was approximately -2.0°C (28.4°F) but his house was inadequately heated. His rectal temperature was 29.5°C (85.1°F). Goiter was not palpable and pitting edema, not myxedema, was present. Serum TSH was elevated (28.3 mU/L, reference range 0.27-4.2), and free T(3) (FT(3)) and free thyroxine (FT(4)) lowered (FT(3), 3.25 pmol/L with a reference range of 4.00-7.85, and FT(4), 9.18 pmol/L with a reference range of 12.87-23.179), but thyroid-related autoantibodies were all negative. By the next morning, body temperature had risen to >36°C (>96.8°F) and there was no further recurrence of hypothermia. Serum TSH decreased exponentially and the patient's condition had become normal by day 22. FT(3) and FT(4) were found to be slightly lowered and elevated, respectively, during the same period, in the subnormal range. At the end of the observation period, the patient settled into the state known as "nonthyroidal illness syndrome." SUMMARY Elevation of TSH in an elderly patient with accidental hypothermia was normalized after restoration of normal body temperature. Elevation of TSH upon accidental hypothermia was probably an adaptive response. CONCLUSIONS In patients with accidental hypothermia, the possibility of an adaptive elevation of TSH should be borne in mind. This clearly warrants further studies of the adaptation of the pituitary-thyroid axis in patients with accidental hypothermia.
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Gutiérrez-Mariscal M, Sánchez E, García-Vázquez A, Rebolledo-Solleiro D, Charli JL, Joseph-Bravo P. Acute response of hypophysiotropic thyrotropin releasing hormone neurons and thyrotropin release to behavioral paradigms producing varying intensities of stress and physical activity. ACTA ACUST UNITED AC 2012; 179:61-70. [PMID: 22960404 DOI: 10.1016/j.regpep.2012.08.010] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2012] [Revised: 07/04/2012] [Accepted: 08/27/2012] [Indexed: 10/27/2022]
Abstract
The activity of the hypothalamus-pituitary-thyroid (HPT) axis is essential for energy homeostasis and is differentially modulated by physical and by psychological stress. Contradictory effects of stressful behavioral paradigms on TSH or thyroid hormone release are due to type, length and controllability of the stressor. We hypothesized that an additional determinant of the activity of the HPT axis is the energy demand due to physical activity. We thus evaluated the response of thyrotropin releasing hormone (TRH) neurons of the hypothalamic paraventricular nucleus (PVN) in Wistar male rats submitted to the elevated plus maze (EPM), the open field test (OFT), or restraint, and sacrificed within 1h after test completion; the response to OFT was compared during light (L) or dark (D) phases. Locomotion and anxiety behaviors were similar if animals were tested in L or D phases but their relation to the biochemical parameters differed. All paradigms increased serum corticosterone concentration; the levels of corticotropin releasing hormone receptor 1 and of glucocorticoid receptor (GR) mRNAs in the PVN were enhanced after restraint or OFT-L. Levels of proTRH mRNA increased in the PVN after exposure to EPM-L or OFT-D; serum levels of thyrotropin (TSH) and T(4) only after OFT-D. In contrast, restraint decreased TRH mRNA and serum TSH levels, while it increased TRH content in the mediobasal hypothalamus, implying reduced release. Expression of proTRH in the PVN varied proportionally to the degree of locomotion in OFT-D, while inversely to anxiety in the EPM-L, and to corticosterone in EPM-L and OFT-D. TRH mRNA levels were analyzed by in situ hybridization in the rostral, middle and caudal zones of the PVN in response to OFT-D; they increased in the middle PVN, where most TRH hypophysiotropic neurons reside; levels correlated positively with the velocity attained in the periphery of the OF and negatively, with anxiety. Variations of serum TSH levels correlated positively with locomotor activity in EPM-L and OFT-L or -D, while negatively to serum corticosterone levels in all paradigms. These results support the proposal that the hypophysiotropic PVN TRH neurons are activated by short term physical activity but that this response may be blunted by the inhibitory effect of stress.
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Affiliation(s)
- Mariana Gutiérrez-Mariscal
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México (UNAM), Cuernavaca MOR, México
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Currás-Collazo MC. Nitric oxide signaling as a common target of organohalogens and other neuroendocrine disruptors. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART B, CRITICAL REVIEWS 2011; 14:495-536. [PMID: 21790323 DOI: 10.1080/10937404.2011.578564] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Organohalogen compounds such as polychlorinated biphenyls (PCB) and polybrominated diphenyl ethers (PBDE) are global environmental pollutants and highly persistent, bioaccumulative chemicals that produce adverse effects in humans and wildlife. Because of the widespread use of these organohalogens in household items and consumer products, indoor contamination is a significant source of human exposure, especially for children. One significant concern with regard to health effects associated with exposure to organohalogens is endocrine disruption. Toxicological studies on organohalogen pollutants primarily focused on sex steroid and thyroid hormone actions, and findings have largely shaped the way one envisions their disruptive effects occurring. Organohalogens exert additional effects on other systems including other complex endocrine systems that may be disregulated at various levels of organization. Over the last 20 years evidence has mounted in favor of a critical role of nitric oxide (NO) in numerous functions ranging from neuroendocrine functions to learning and memory. With its participation in multiple systems and action at several levels of integration, NO signaling has a pervasive influence on nervous and endocrine functions. Like blockers of NO synthesis, PCBs and PBDEs produce multifaceted effects on physiological systems. Based on this unique set of converging information it is proposed that organohalogen actions occur, in part, by hijacking processes associated with this ubiquitous bioactive molecule. The current review examines the emerging evidence for NO involvement in selected organohalogen actions and includes recent progress from our laboratory that adds to our current understanding of the actions of organohalogens within hypothalamic neuroendocrine circuits. The thyroid, vasopressin, and reproductive systems as well as processes associated with long-term potentiation were selected as sample targets of organohalogens that rely on regulation by NO. Information is provided about other toxicants with demonstrated interference of NO signaling. Our focus on the convergence between NO system and organohalogen toxicity offers a novel approach to understanding endocrine and neuroendocrine disruption that is particularly problematic for developing organisms. This new working model is proposed as a way to encourage future study in elucidating common mechanisms of action that are selected with a better operational understanding of the systems affected.
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Affiliation(s)
- Margarita C Currás-Collazo
- Department of Cell Biology and Neuroscience, University of California, Riverside, Riverside, California 92521, USA.
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