scholarly journals Regulation and adaptation of endocrine axes at high altitude

2020 ◽  
Vol 318 (2) ◽  
pp. E297-E309
Author(s):  
Daniel M. Keenan ◽  
Jacqueline Pichler Hefti ◽  
Johannes D. Veldhuis ◽  
Michael Von Wolff
Keyword(s):  
Thyroid Stimulating Hormone ◽  
Free Thyroxine ◽  
The Body ◽  
Pituitary Hormone ◽  
Control Mechanisms ◽  
False Discovery Rates ◽  
False Discovery ◽  
Base Camp ◽  
Extreme Altitude ◽  
Thyroid Axis

As a model of extreme conditions, eight healthy women, part of a 40-member Nepal mountain-climbing expedition, were monitored for dynamic endocrine adaptations. Endocrine measurements were made at frequent intervals over a 6–10-h period at four altitudes: 450 m, 4,800 m (base camp), 6,050 m, and again at 4,800 m (on descent) after an acclimatization (A) period (4,800 mA). Quantified hormones were growth hormone (GH), prolactin (PROL), cortisol (Cort), thyroid-stimulating hormone (TSH), and free thyroxine. These hormones are important to the anabolic/catabolic balance of the body, and are vital to growth, homeostasis, hypothalamic inhibition, regulation of stress, and metabolism. A key secondary question was the degree to which acclimatization can stabilize hormonal disruption. On the basis of statistical false discovery rates, the present analyses unveil marked adaptive changes in the thyroid axis at the level of pulsatile secretion of the pituitary hormone TSH and its downstream product, free thyroxine; strong effects on the mass of GH, TSH, Cort, and PROL secretion per burst; and prominent pulsatile frequency disruption and recovery for PROL and Cort. Because pulsatility changes reflect de facto perturbations in hypothalamo-pituitary control mechanisms, the present data introduce the concept of both frequency- and amplitude-dependent adaptive control of brain-pituitary neuroendocrine signals under conditions of extreme altitude exertion and exposure.

The Pituitary Gland: Embryology, Physiology, and Pathophysiology

2000 ◽  
Vol 19 (2) ◽  
pp. 9-17 ◽  
Author(s):  
Angela Dorton
Keyword(s):  
Pituitary Gland ◽  
Anterior Pituitary ◽  
Pituitary Hormones ◽  
Thyroid Stimulating Hormone ◽  
The Body ◽  
Pars Intermedia ◽  
Pituitary Hormone ◽  
Pars Tuberalis ◽  
Pars Distalis ◽  
Stimulating Hormone

The pituitary gland, the “master gland” of the body, is composed of endocrine cells, which secrete hormones essential for homeostasis. The gland consists of the adenohypophysis (anterior pituitary) and the neurohypophysis (posterior pituitary), two unique structures that differ anatomically and functionally.The neurohypophysis is innervated by nerve cells in the hypothalamus and forms the connection between it and the pituitary gland. The hypothalamus stimulates release and inhibition of pituitary hormones. The neurohypophysis secretes oxytocin and antidiuretic hormone.The adenohypophysis is composed of three structures: the pars distalis, the pars intermedia, and the pars tuberalis. The anterior pituitary (pars distalis) is responsible for the release of hormones that include growth hormone, prolactin, thyroid-stimulating hormone, follicle-stimulating hormone, luteinizing hormone, adrenocorticotropic hormone, and melanocyte-stimulating hormone.Disorders of the pituitary are predominately those of insufficient hormone release and may have profound effects on the neonate. The potential causes of and clinical symptomatology that may accompany pituitary hormone insufficiency in the neonatal period are explored.

scholarly journals Dynamic Interactions Between the Immune System and the Neuroendocrine System in Health and Disease

2021 ◽  
Vol 12 ◽  
Author(s):  
John R. Klein
Keyword(s):  
Immune System ◽  
Splice Variant ◽  
Thyroid Stimulating Hormone ◽  
Neuroendocrine System ◽  
The Body ◽  
Control Mechanisms ◽  
Autoimmune Thyroid ◽  
Hormone Synthesis ◽  
New Findings ◽  
Hand Control

The immune system and the neuroendocrine system share many common features. Both consist of diverse components consisting of receptors and networks that are widely distributed throughout the body, and both sense and react to external stimuli which, on the one hand control mechanisms of immunity, and on the other hand control and regulate growth, development, and metabolism. It is thus not surprising, therefore, that the immune system and the neuroendocrine system communicate extensively. This article will focus on bi-directional immune-endocrine interactions with particular emphasis on the hormones of the hypothalamus-pituitary-thyroid (HPT) axis. New findings will be discussed demonstrating the direct process through which the immune system-derived thyroid stimulating hormone (TSH) controls thyroid hormone synthesis and bone metamorphosis, particularly in the context of a novel splice variant of TSHβ made by peripheral blood leukocytes (PBL). Also presented are the ways whereby the TSHβ splice variant may be a contributing factor in the development and/or perpetuation of autoimmune thyroid disease (AIT), and how systemic infection may elicit immune-endocrine responses. The relationship between non-HPT hormones, in particular adipose hormones, and immunity is discussed.

scholarly journals A study of Some Hormones and Antioxidant ‎Systems Disturbances in Older Men

2018 ◽  
Vol 26 (4) ◽  
pp. 268-281
Author(s):  
Reem Abdul-Raheem Al-Saadi ◽  
Dakhel Ghani Al-Watify
Keyword(s):  
Glutathione Peroxidase ◽  
Reduced Glutathione ◽  
Older Men ◽  
Thyroid Stimulating Hormone ◽  
The Body ◽  
Antioxidant Systems ◽  
Control Group ◽  
Physiological Phenomenon ◽  
Younger Men ◽  
Thyroid Axis

     Ageing is a physiological phenomenon that manifested itself with disturbances of many homeostatic regulating mechanisms of the body . The present study was conducted and employed to investigate two major systems( hormones and antioxidant systems) that can be implicated in progress of aging .The total number of subjects included in the present study was fifty (50) healthy men and classified according to their ages into two groups, the first group included 25 younger men (control group) and their ages ranged between 21 to 30 years old whereas the second group included 25 older men and their ages were between 61 to 70 years old.  Data obtained from this study indicated a significant decrease(p<0.05) in the levels of thyroid stimulating hormone (TSH) which is associated with marked elevation (p<0.05) of triiodothyronine(T3) and tetraiodothyronine(T4) of older men when compared with younger men. In regard to levels of cortisol and testosterone hormones were significantly decreased (p<0.05) in aged men when matched with their counterparts of younger men.  Concerning concentrations of malondehyde (MDA) ,a final product of lipid peroxidation, confirmed a remarkable elevation (p<0.05) in older men compared to younger men and these results were associated with significant lowering (p<0.05) in the activities of antioxidant components including glutathione peroxidase (GPX), reduced glutathione (GSH) and catalase . In addition , there are no significant  correlations(p>0.05) occurring among hormones( testosterone  , T3) and glutathione peroxidase and of malondehyde .   From these results ,one can be concluded that with ageing there are many disturbances and fluctuations of hypothalamic-adrenal and thyroid axis that accompanied with drop of essential antioxidant components that may be lead to suppress of defense against free radicals and the present study concluded that the changes occurring in studied hormones have not relations and effects on the antioxidant systems.

Establishment of Early Pregnancy Related Thyroid Hormone Models and Reference Intervals for Pregnant Women in China Based on Real World Data

2021 ◽  
Vol 53 (04) ◽  
pp. 272-279
Author(s):  
Chaochao Ma ◽  
Xiaoqi Li ◽  
Lixin Liu ◽  
Xinqi Cheng ◽  
Fang Xue ◽  
...  
Keyword(s):  
Thyroid Hormone ◽  
Thyroid Hormones ◽  
Pregnant Women ◽  
Early Pregnancy ◽  
Gestational Age ◽  
Dynamic Change ◽  
Reference Intervals ◽  
Thyroid Stimulating Hormone ◽  
Free Thyroxine ◽  
Stimulating Hormone

AbstractThyroid hormone reference intervals are crucial for diagnosing and monitoring thyroid dysfunction during early pregnancy, and the dynamic change trend of thyroid hormones during pregnancy can assist clinicians to assess the thyroid function of pregnant women. This study aims to establish early pregnancy related thyroid hormones models and reference intervals for pregnant women. We established two derived databases: derived database* and derived database#. Reference individuals in database* were used to establish gestational age-specific reference intervals for thyroid hormones and early pregnancy related thyroid hormones models for pregnant women. Individuals in database# were apparently healthy non-pregnant women. The thyroid hormones levels of individuals in database# were compared with that of individuals in database* using nonparametric methods and the comparative confidence interval method. The differences in thyroid stimulating hormone and free thyroxine between early pregnant and non-pregnant women were statistically significant (p<0.0001). The reference intervals of thyroid stimulating hormone, free thyroxine and free triiodothyronine for early pregnant women were 0.052–3.393 μIU/ml, 1.01–1.54 ng/dl, and 2.51–3.66 pg/ml, respectively. Results concerning thyroid stimulating hormone and free thyroxine reference intervals of early pregnancy are comparable with those from other studies using the same detection platform. Early pregnancy related thyroid hormones models showed various change patterns with gestational age for thyroid hormones. Early pregnancy related thyroid hormones models and reference intervals for pregnant women were established, so as to provide accurate and reliable reference basis for the diagnosing and monitoring of maternal thyroid disfunction in early pregnancy.

scholarly journals Interconversion of Plasma Free Thyroxine Values from Assay Platforms with Different Reference Intervals Using Linear Transformation Methods

Biology ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 45
Author(s):  
Fanwen Meng ◽  
Jacqueline Jonklaas ◽  
Melvin Khee-Shing Leow
Keyword(s):  
Linear Transformation ◽  
Piecewise Linear ◽  
Equilibrium Dialysis ◽  
Accurate Method ◽  
Reference Intervals ◽  
Thyroid Stimulating Hormone ◽  
Free Thyroxine ◽  
Thyroid Function Tests ◽  
Linear Transformations ◽  
Transformation Methods

Clinicians often encounter thyroid function tests (TFT) comprising serum/plasma free thyroxine (FT4) and thyroid stimulating hormone (TSH) measured using different assay platforms during the course of follow-up evaluations which complicates reliable comparison and interpretation of TFT changes. Although interconversion between concentration units is straightforward, the validity of interconversion of FT4/TSH values from one assay platform to another with different reference intervals remains questionable. This study aims to establish an accurate and reliable methodology of interconverting FT4 by any laboratory to an equivalent FT4 value scaled to a reference range of interest via linear transformation methods. As a proof-of-concept, FT4 was simultaneously assayed by direct analog immunoassay, tandem mass spectrometry and equilibrium dialysis. Both linear and piecewise linear transformations proved relatively accurate for FT4 inter-scale conversion. Linear transformation performs better when FT4 are converted from a more accurate to a less accurate assay platform. The converse is true, whereby piecewise linear transformation is superior to linear transformation when converting values from a less accurate method to a more robust assay platform. Such transformations can potentially apply to other biochemical analytes scale conversions, including TSH. This aids interpretation of TFT trends while monitoring the treatment of patients with thyroid disorders.

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

Method specific second-trimester reference intervals for thyroid-stimulating hormone and free thyroxine

2009 ◽  
Vol 42 (7-8) ◽  
pp. 750-753 ◽  
Author(s):  
Rechelle Silvio ◽  
Karly J. Swapp ◽  
Sonia L. La'ulu ◽  
Kara Hansen-Suchy ◽  
William L. Roberts
Keyword(s):  
Reference Intervals ◽  
Thyroid Stimulating Hormone ◽  
Free Thyroxine ◽  
Second Trimester ◽  
Stimulating Hormone

Preterm to term infant postmenstrual age reference intervals for thyroid-stimulating hormone and free thyroxine

2021 ◽  
Author(s):  
George M. Ziegler ◽  
Jonathan L. Slaughter ◽  
Monika Chaudhari ◽  
Herveen Singh ◽  
Pablo J. Sánchez ◽  
...  
Keyword(s):  
Reference Intervals ◽  
Thyroid Stimulating Hormone ◽  
Term Infant ◽  
Free Thyroxine ◽  
Postmenstrual Age ◽  
Stimulating Hormone
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