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

Systemic effects of 1,25-dihydroxyvitamin D3 on the pituitary-hypothalamic axis in rats

1987 ◽  
Vol 115 (2) ◽  
pp. 225-228 ◽  
Author(s):  
K. Törnquist ◽  
C. Lamberg-Allardt
Keyword(s):  
Hormone Secretion ◽  
Dihydroxyvitamin D3 ◽  
Hydroxyvitamin D ◽  
Dihydroxyvitamin D ◽  
1,25 Dihydroxyvitamin D ◽  
Pituitary Thyroid Axis ◽  
Thyroid Axis ◽  
25 Hydroxyvitamin D ◽  
Wet Weight ◽  
Indirect Action

Abstract. Treatment of rats with 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) 0.05 μg/kg per day for three days was without any effect on serum T3, T4 or TSH concentrations, whereas serum PRL increased (20.6 ± 3.8 to 76.2 ± 19.1 μg/l, mean ± sem, N = 7–8; P < 0.01). Increased hypothalamic TRH levels (24.3 ± 3.9 to 45.7 ± 7.8 pmol/g wet weight; P < 0.01) may indicate an effect of 1,25(OH)2D3 on hypothalamic TRH homeostasis. This effect could probably be due to an indirect action of 1,25(OH)2D3, mediated by the increased serum calcium (2.77 ± 0.02 to 3.16 ± 0.08 mmol/l, mean ± sem, N = 7–8; P < 0.001). This assumption was, however, not tested. Neither the pituitary TSH nor PRL was affected. The treatment decreased the serum concentration of 25-hydroxyvitamin D3 (23.0 ± 1.3 to 16.8 ± 2.0 nmol/l, mean ± sem, N = 5–7; P < 0.01) and of 24,25-dihydroxyvitamin D3 (3.2 ± 0.3 to 2.1 ± 0.1 nmol/l, mean ± sem, N = 3–5; P < 0.05). The results show that in this experimental design, 1,25(OH)2D3 has no effect on basal hormone secretion from the pituitary-thyroid axis, and that 1,25(OH)2D3 decreases the synthesis of the vitamin D3 metabolites studied.

scholarly journals Disruption of the Melanin-Concentrating Hormone Receptor 1 (MCH1R) Affects Thyroid Function

Endocrinology ◽  
2012 ◽  
Vol 153 (12) ◽  
pp. 6145-6154 ◽  
Author(s):  
Shinjae Chung ◽  
Xiao-Hui Liao ◽  
Caterina Di Cosmo ◽  
Jacqueline Van Sande ◽  
Zhiwei Wang ◽  
...  
Keyword(s):  
Thyroid Function ◽  
Hormone Secretion ◽  
Zona Incerta ◽  
Wild Type ◽  
Free T4 ◽  
Thyroid Follicular Cells ◽  
Pituitary Thyroid Axis ◽  
Melanin Concentrating Hormone ◽  
Thyroid Axis ◽  
Follicle Size

Abstract Melanin-concentrating hormone (MCH) is a peptide produced in the hypothalamus and the zona incerta that acts on one receptor, MCH receptor 1 (MCH1R), in rodents. The MCH system has been implicated in the regulation of several centrally directed physiological responses, including the hypothalamus-pituitary-thyroid axis. Yet a possible direct effect of the MCH system on thyroid function has not been explored in detail. We now show that MCH1R mRNA is expressed in thyroid follicular cells and that mice lacking MCH1R [MCH1R-knockout (KO)] exhibit reduced circulating iodothyronine (T4, free T4, T3, and rT3) levels and high TRH and TSH when compared with wild-type (WT) mice. Because the TSH of MCH1R-KO mice displays a normal bioactivity, we hypothesize that their hypothyroidism may be caused by defective thyroid function. Yet expression levels of the genes important for thyroid hormones synthesis or secretion are not different between the MCH1R-KO and WT mice. However, the average thyroid follicle size of the MCH1R-KO mice is larger than that of WT mice and contained more free and total T4 and T3 than the WT glands, suggesting that they are sequestered in the glands. Indeed, when challenged with TSH, the thyroids of MCH1R-KO mice secrete lower amounts of T4. Similarly, secretion of iodothyronines in the plasma upon 125I administration is significantly reduced in MCH1R-KO mice. Therefore, the absence of MCH1R affects thyroid function by disrupting thyroid hormone secretion. To our knowledge, this study is the first to link the activity of the MCH system to the thyroid function.

Interleukin 6 effects on the pituitary–thyroid axis in the rat

1994 ◽  
Vol 131 (3) ◽  
pp. 302-306 ◽  
Author(s):  
Luigi Bartalena ◽  
Lucia Grasso ◽  
Sandra Brogioni ◽  
Enio Martino
Keyword(s):  
Thyroid Hormone ◽  
Interleukin 6 ◽  
Saline Solution ◽  
Hormone Secretion ◽  
Neutralizing Antibody ◽  
Control Group ◽  
Apparent Lack ◽  
Tnf Α ◽  
Pituitary Thyroid Axis ◽  
Thyroid Axis

Bartalena L, Grasso L, Brogioni S, Martino E. Interleukin 6 effects on the pituitary–thyroid axis in the rat. Eur J Endocrinol 1994;131:302–6. ISSN 0804–4643 It has been postulated recently that cytokines, and in particular interleukin 1 (IL-1) and tumor necrosis factor-α TNF-α), may have a role in the pathogenesis of the changes of serum thyroid hormone concentrations that are encountered in patients with non-thyroidal illness (NTI). Many of the IL-1 and TNF-α effects are believed to be mediated by the induction of IL-6 synthesis, which might, therefore, represent an important mediator of thyroid hormone changes in NTI. To address this problem, male Wistar rats were injected subcutaneously with 2.5 μg of recombinant human IL-6 (rhIL-6, in 500 μl of saline solution), with 2.5 μg of rhIL-6 preincubated with 100 μl of anti-IL-6 neutralizing antibody or with saline solution alone (control group). Administration of rhIL-6 resulted in a significant decrease of thyroxine (T4) from 82 ± 4 nmol/l (mean± sem) to a nadir of 33 ± 3 nmol/l (p < 0.0001) after 48 h, and of triiodothyronine (T3) from 1.6 ± 0.1 to 0.8 ± 0.1 nmol/l after 48 h (p < 0.0001). A slight decrease in serum T4 and T3 concentrations also was observed in the control group, but the lowest values (T4, 66 ± 3 nmol/l; T3, 1.2 ± 0.1 nmol/l) were significantly higher (p < 0.0001) than in IL-6-treated rats. The IL-6-induced changes could be prevented by preincubation of rhIL-6 with its neutralizing antibody. Slight but not significant changes occurred in serum reverse T3 (rT3) concentration, so that the T4/rT3 ratio remained substantially unchanged after rhIL-6 injection, whereas the T4/T3 ratio decreased significantly from 53.6 to 39.9 (p < 0.02) in IL-6-treated rats. The effects of IL-6 on thyrotropin (TSH) were investigated after rendering the rats hypothyroid by methimazole administration for 3 weeks. Serum TSH decreased from 19.0 ± 6.8 to 13.3 ± 3.8 μg/l after 48 h (p < 0.01) in IL-6-treated rats, while it increased from 17.2 ± 2.8 to 25.8 ± 4.0 μg/l (p < 0.01) in the control group. These results show that a single injection of rhIL-6 causes a decrease in serum T4, T3 and TSH concentrations in the rat, without affecting serum rT3 levels. This is compatible with a predominantly central effect of the cytokine. The apparent lack of inhibition of 5′-deiodinating activity, a key feature of NTI, suggests that IL-6, if involved, is only one of the factors responsible for the changes of thyroid hormone secretion and metabolism observed in NTI. Luigi Bartalena, Istituto di Endocrinologia, University of Pisa, Viale del Tirreno 64, 56018 Tirrenia-Pisa, Italy

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

The Pituitary-Thyroid Axis in Adults with Phenylketonuria

1976 ◽  
Vol 42 (6) ◽  
pp. 1179-1181 ◽  
Author(s):  
R. M. STEWART ◽  
S. HEMLI ◽  
G. H. DANIELS ◽  
E. H. KOLODNY ◽  
F. MALOOF
Keyword(s):  
Pituitary Thyroid Axis ◽  
Thyroid Axis
Sign in / Sign up

Export Citation Format

Share Document