scholarly journals The central melanocortin system affects the hypothalamo-pituitary thyroid axis and may mediate the effect of leptin

2000 ◽  
Vol 105 (7) ◽  
pp. 1005-1011 ◽  
Author(s):  
M.S. Kim ◽  
C.J. Small ◽  
S.A Stanley ◽  
D.G.A. Morgan ◽  
L.J. Seal ◽  
...  
Keyword(s):  
Melanocortin System ◽  
Pituitary Thyroid Axis ◽  
Thyroid Axis

scholarly journals Type 3 Deiodinase Role on Central Thyroid Hormone Action Affects the Leptin-Melanocortin System and Circadian Activity

Endocrinology ◽  
2016 ◽  
Vol 158 (2) ◽  
pp. 419-430 ◽  
Author(s):  
Zhaofei Wu ◽  
M. Elena Martinez ◽  
Donald L. St. Germain ◽  
Arturo Hernandez
Keyword(s):  
Energy Balance ◽  
Elevated Serum ◽  
Serum Levels ◽  
Leptin Resistance ◽  
Melanocortin System ◽  
White Adipocyte ◽  
Pituitary Thyroid Axis ◽  
Thyroid Axis ◽  
The Central Nervous System ◽  
Type 3

Abstract The role of thyroid hormones (THs) in the central regulation of energy balance is increasingly appreciated. Mice lacking the type 3 deiodinase (DIO3), which inactivates TH, have decreased circulating TH levels relative to control mice as a result of defects in the hypothalamic-pituitary-thyroid axis. However, we have shown that the TH status of the adult Dio3−/− brain is opposite that of the serum, exhibiting enhanced levels of TH action. Because the brain, particularly the hypothalamus, harbors important circuitries that regulate metabolism, we aimed to examine the energy balance phenotype of Dio3−/− mice and determine whether it is associated with hypothalamic abnormalities. Here we show that Dio3−/− mice of both sexes exhibit decreased adiposity, reduced brown and white adipocyte size, and enhanced fat loss in response to triiodothyronine (T3) treatment. They also exhibit increased TH action in the hypothalamus, with abnormal expression and T3 sensitivity of genes integral to the leptin-melanocortin system, including Agrp, Npy, Pomc, and Mc4r. The normal to elevated serum levels of leptin, and elevated and repressed expression of Agrp and Pomc, respectively, suggest a profile of leptin resistance. Interestingly, Dio3−/− mice also display elevated locomotor activity and increased energy expenditure. This occurs in association with expanded nighttime activity periods, suggesting a disrupted circadian rhythm. We conclude that DIO3-mediated regulation of TH action in the central nervous system influences multiple critical determinants of energy balance. Those influences may partially compensate each other, with the result likely contributing to the decreased adiposity observed in Dio3−/− mice.

scholarly journals Interactions between the melanocortin system and the hypothalamo–pituitary–thyroid axis

Peptides ◽  
2006 ◽  
Vol 27 (2) ◽  
pp. 333-339 ◽  
Author(s):  
Niamh M. Martin ◽  
Kirsty L. Smith ◽  
Stephen R. Bloom ◽  
Caroline J. Small
Keyword(s):  
Melanocortin System ◽  
Pituitary Thyroid Axis ◽  
Thyroid Axis

scholarly journals Fasting-Induced Changes in Hepatic Thyroid Hormone Metabolism in Male Rats Are Independent of Autonomic Nervous Input to the Liver

Endocrinology ◽  
2014 ◽  
Vol 155 (12) ◽  
pp. 5033-5041 ◽  
Author(s):  
E.M. de Vries ◽  
L. Eggels ◽  
H.C van Beeren ◽  
M.T. Ackermans ◽  
A. Kalsbeek ◽  
...  
Keyword(s):  
Thyroid Hormone ◽  
Male Rats ◽  
Melanocortin System ◽  
Humoral Factors ◽  
Autonomic Nervous ◽  
Pituitary Thyroid Axis ◽  
Serum T3 ◽  
Thyroid Axis ◽  
Induced Changes ◽  
Expression And Activity

During fasting, profound changes in the regulation of the hypothalamus-pituitary-thyroid axis occur in order to save energy and limit catabolism. In this setting, serum T3 and T4 are decreased without an appropriate TSH and TRH response reflecting central down-regulation of the hypothalamus-pituitary-thyroid axis. Hepatic thyroid hormone (TH) metabolism is also affected by fasting, because type 3 deiodinase (D3) is increased, which is mediated by serum leptin concentrations. A recent study showed that fasting-induced changes in liver TH sulfotransferases (Sults) and uridine 5′-diphospho-glucuronosyltransferase (Ugts) depend on a functional melanocortin system in the hypothalamus. However, the pathways connecting the hypothalamus and the liver that induce these changes are currently unknown. In the present study, we investigated in rats whether the fasting-induced changes in hepatic TH metabolism are regulated by the autonomic nervous system. We selectively cut either the sympathetic or the parasympathetic input to the liver. Serum and liver TH concentrations, deiodinase expression, and activity and Sult and Ugt expression were measured in rats that had been fasted for 36 hours or were fed ad libitum. Fasting decreased serum T3 and T4 concentrations, whereas intrahepatic TH concentrations remained unchanged. D3 expression and activity increased, as was the expression of constitutive androstane receptor, Sult1b1, and Ugt1a1, whereas liver D1 was unaffected. Neither sympathetic nor parasympathetic denervation affected the fasting-induced alterations. We conclude that fasting-induced changes in liver TH metabolism are not regulated via the hepatic autonomic input in a major way and more likely reflect a direct effect of humoral factors on the hepatocyte.

Effect of melatonin on hormone secretion and tissue ultrastructure of hypothalamus-pituitary-thyroid axis in rats

2009 ◽  
Vol 29 (9) ◽  
pp. 1009-1012
Author(s):  
Yi BAO ◽  
Le BU ◽  
Jun-jie ZOU ◽  
Yong-quan SHI ◽  
Zhi-min LIU
Keyword(s):  
Hormone Secretion ◽  
Pituitary Thyroid Axis ◽  
Thyroid Axis ◽  
Tissue Ultrastructure

The impact of oral hormonal contraception on metformin action on hypothalamic‐pituitary‐thyroid axis activity in women with diabetes and prediabetes: A pilot study

2020 ◽  
Vol 45 (5) ◽  
pp. 937-945 ◽  
Author(s):  
Robert Krysiak ◽  
Karolina Kowalcze ◽  
Monika Wolnowska ◽  
Bogusław Okopień
Keyword(s):  
Pilot Study ◽  
Hormonal Contraception ◽  
Pituitary Thyroid Axis ◽  
Thyroid Axis ◽  
The Impact

scholarly journals Chronothyroidology: Chronobiological Aspects in Thyroid Function and Diseases

Life ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 426
Author(s):  
Giuseppe Bellastella ◽  
Maria Ida Maiorino ◽  
Lorenzo Scappaticcio ◽  
Annamaria De Bellis ◽  
Silvia Mercadante ◽  
...  
Keyword(s):  
Thyroid Function ◽  
Biological Rhythms ◽  
Cellular Level ◽  
Scientific Discipline ◽  
Biological Phenomena ◽  
Pituitary Thyroid Axis ◽  
Circadian Organization ◽  
Thyroid Axis ◽  
Central Clock ◽  
Thyroid Dysfunctions

Chronobiology is the scientific discipline which considers biological phenomena in relation to time, which assumes itself biological identity. Many physiological processes are cyclically regulated by intrinsic clocks and many pathological events show a circadian time-related occurrence. Even the pituitary–thyroid axis is under the control of a central clock, and the hormones of the pituitary–thyroid axis exhibit circadian, ultradian and circannual rhythmicity. This review, after describing briefly the essential principles of chronobiology, will be focused on the results of personal experiences and of other studies on this issue, paying particular attention to those regarding the thyroid implications, appearing in the literature as reviews, metanalyses, original and observational studies until 28 February 2021 and acquired from two databases (Scopus and PubMed). The first input to biological rhythms is given by a central clock located in the suprachiasmatic nucleus (SCN), which dictates the timing from its hypothalamic site to satellite clocks that contribute in a hierarchical way to regulate the physiological rhythmicity. Disruption of the rhythmic organization can favor the onset of important disorders, including thyroid diseases. Several studies on the interrelationship between thyroid function and circadian rhythmicity demonstrated that thyroid dysfunctions may affect negatively circadian organization, disrupting TSH rhythm. Conversely, alterations of clock machinery may cause important perturbations at the cellular level, which may favor thyroid dysfunctions and also cancer.

scholarly journals OctylPhenol (OP) Alone and in Combination with NonylPhenol (NP) Alters the Structure and the Function of Thyroid Gland of the Lizard Podarcis siculus

2021 ◽  
Vol 80 (3) ◽  
pp. 567-578 ◽  
Author(s):  
Rosaria Sciarrillo ◽  
Mariana Di Lorenzo ◽  
Salvatore Valiante ◽  
Luigi Rosati ◽  
Maria De Falco
Keyword(s):  
Thyroid Gland ◽  
Endocrine Disrupting Chemicals ◽  
Thyroid Stimulating Hormone ◽  
Control Group ◽  
Type Ii ◽  
Endocrine Disrupting ◽  
Pituitary Thyroid Axis ◽  
Podarcis Siculus ◽  
Thyroid Axis ◽  
By Products

Abstract Different environmental contaminants disturb the thyroid system at many levels. AlkylPhenols (APs), by-products of microbial degradation of AlkylPhenol Polyethoxylates (APEOs), constitute an important class of Endocrine Disrupting Chemicals (EDCs), the two most often used environmental APs being 4-nonylphenol (4-NP) and 4-tert-octylphenol (4-t-OP). The purpose of the present study was to investigate the effects on the thyroid gland of the bioindicator Podarcis siculus of OP alone and in combination with NP. We used radioimmunoassay to determine their effects on plasma 3,3′,5-triiodo-L-thyronine (T3), 3,3′,5,5′-L-thyroxine (T4), thyroid-stimulating hormone (TSH), and thyrotropin-releasing hormone (TRH) levels in adult male lizards. We also investigated the impacts of AP treatments on hepatic 5′ORD (type II) deiodinase and hepatic content of T3 and T4. After OP and OP + NP administration, TRH levels increased, whereas TSH, T3, and T4 levels decreased. Lizards treated with OP and OP + NP had a higher concentration of T3 in the liver and 5′ORD (type II) activity, whereas T4 concentrations were lower than that observed in the control group. Moreover, histological examination showed that the volume of the thyroid follicles became smaller in treated lizards suggesting that that thyroid follicular epithelial cells were not functionally active following treatment. This data collectively suggest a severe interference with hypothalamus–pituitary–thyroid axis and a systemic imbalance of thyroid hormones. Graphic Abstract

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