scholarly journals Dependency of Maximum Goitrogenic Response on Some Minimal Level of Thyroid Hormone Production

1981 ◽  
Vol 60 (4) ◽  
pp. 846-854 ◽  
Author(s):  
B.E. MARCH ◽  
RAYMOND POON
Keyword(s):  
Thyroid Hormone ◽  
Minimal Level ◽  
Hormone Production

Thyrotrophin-producing pituitary adenomas

1982 ◽  
Vol 57 (4) ◽  
pp. 515-519 ◽  
Author(s):  
Stephen A. Hill ◽  
James M. Falko ◽  
Charles B. Wilson ◽  
William E. Hunt
Keyword(s):  
Thyroid Hormone ◽  
Pituitary Adenomas ◽  
Preoperative Diagnosis ◽  
Pituitary Tumors ◽  
Recurrent Tumor ◽  
Hormone Production ◽  
Content Type ◽  
Aggressive Tumor ◽  
Tsh Levels ◽  
Fine Print

✓ Hyperthyroidism due to thyrotrophin (TSH)-secreting pituitary tumors is rare. Four cases are described, with the features that allow preoperative diagnosis. In all the patients, thyroid hormone production was consistently elevated despite antithyroid therapy, and TSH levels were inappropriately elevated. All patients were treated with both surgery and irradiation. Each patient had recurrent tumor with suprasellar, intrasphenoidal, or intraorbital spread. The combination of a recurrent, aggressive tumor complicated by thyrotoxicosis makes this a complex and difficult surgical problem.

Factors Affecting Glucocorticoid and Thyroid Hormone Production of Island Foxes

2019 ◽  
Vol 84 (3) ◽  
pp. 505-514
Author(s):  
Corinne P. Kozlowski ◽  
Helen Clawitter ◽  
Angela Guglielmino ◽  
Juliann Schamel ◽  
Stacy Baker ◽  
...  
Keyword(s):  
Thyroid Hormone ◽  
Hormone Production ◽  
Factors Affecting

In vivo effects of flavonoid EMD 21388 on thyroid hormone secretion and metabolism in rats

1991 ◽  
Vol 261 (2) ◽  
pp. E227-E232 ◽  
Author(s):  
J. P. Schroder-van der Elst ◽  
D. van der Heide ◽  
J. Kohrle
Keyword(s):  
Thyroid Hormone ◽  
Hormone Secretion ◽  
Male Rats ◽  
Intact Male ◽  
Hormone Production ◽  
Iodide Uptake ◽  
Brown Adipose ◽  
In Vivo Effects

In vitro, the synthetic flavonoid EMD 21388 appears to be a potent inhibitor of thyroxine (T4) 5'-deiodinase and diminishes binding of T4 to transthyretin. In this study, in vivo effects of long-term administration of EMD 21388 on thyroid hormone production and metabolism were investigated. Intact male rats received EMD 21388 (20 mumol.kg body wt-1.rat-1.day-1) for 14 days. [125I]T4 and 3,5,3'-[131I]triiodotyronine (T3) were infused continuously and intravenously in a double-isotope protocol for the last 10 and 7 days, respectively. EMD 21388 decreased plasma thyroid hormone concentrations, but thyrotropin levels in plasma and pituitary did not change. Plasma clearance rates for T4 and T3 increased. Thyroidal T4 secretion was diminished, but T3 secretion was elevated. Extrathyroidal T3 production by 5'-deiodination was lower. T4 concentrations were markedly lower in all tissues investigated. Total tissue T3 was lower in brown adipose tissue, brain, cerebellum, and pituitary, tissues that express the type II 5'-deiodinase isozyme due to decreased local T3 production. Most tissues showed increased tissue/plasma ratios for T4 and T3. These results indicate that this flavonoid diminished T4 and increased T3 secretion by the thyroid, probably in analogy with other natural flavonoids, by interference with one or several steps between iodide uptake, organification, and hormone synthesis.

Effects of marginal iodine deficiency during pregnancy: iodide uptake by the maternal and fetal thyroid

1997 ◽  
Vol 273 (6) ◽  
pp. E1121-E1126 ◽  
Author(s):  
P. M. Versloot ◽  
J. P. Schröder-Van Der Elst ◽  
D. Van Der Heide ◽  
L. Boogerd
Keyword(s):  
Thyroid Hormone ◽  
Iodine Deficiency ◽  
Specific Activity ◽  
Hormone Production ◽  
Iodide Uptake ◽  
Deficient Diet ◽  
Pregnant Rats ◽  
Thyroid Hormone Metabolism ◽  
Fetal Thyroid ◽  
The Absolute

Iodide uptake by the thyroid is an active process. Iodine deficiency and pregnancy are known to influence thyroid hormone metabolism. The aim of this study was to clarify the effects of iodine deficiency and pregnancy on iodide uptake by the thyroid. Radioiodide was injected intravenously into nonpregnant and 19-day pregnant rats receiving a normal or marginally iodine-deficient diet. The uptake of radioiodide by the thyroid was measured continuously for 4 h. The absolute iodide uptake by the maternal and fetal thyroid glands at 24 h was calculated by means of the urinary specific activity. Pregnancy resulted in a decrease in the absolute thyroidal iodide uptake. Marginal iodine deficiency had no effect on the absolute iodide uptake by the maternal thyroid. The decreased plasma inorganic iodide was compensated by an increase in thyroidal clearance. A similar compensation was not found for the fetus; the uptake of iodide by the fetal thyroid decreased by 50% during marginal iodine deficiency. This can lead to diminished thyroid hormone production, which will have a negative effect on fetal development, especially of the brain.

scholarly journals Ontogeny of pituitary thyrotrophs and regulation by endogenous thyroid hormone feedback in the chick embryo

2005 ◽  
Vol 184 (2) ◽  
pp. 407-416 ◽  
Author(s):  
Michael Muchow ◽  
Ioannis Bossis ◽  
Tom E Porter
Keyword(s):  
Thyroid Hormone ◽  
Thyroid Hormones ◽  
Anterior Pituitary ◽  
Feedback Regulation ◽  
Thyroid Stimulating Hormone ◽  
Mrna Levels ◽  
Hormone Production ◽  
Negative Feedback Regulation ◽  
Cephalic Lobe ◽  
Whole Mount

Increased thyroid hormone production is essential for hatching of the chick and for the increased metabolism necessary for posthatch endothermic life. However, little is known about the ontogeny and distribution of pituitary thyrotrophs during this period or whether pituitary thyroid-stimulating hormone (TSH) production is regulated by endogenous thyroid hormones during chick embryonic development. This study assessed the abundance and location of pituitary thyrotrophs and the regulation of TSHβ peptide and mRNA levels by endogenous thyroid hormones prior to hatching. TSHβ-containing cells were first detected on embryonic day (e) 11, and the thyrotroph population increased to maximum levels on e17 and e19 and then decreased prior to hatching (d1). Thyrotroph distribution within the cephalic lobe of the anterior pituitary was determined on e19 by whole-mount immunocytochemistry for TSHβ peptide and by whole-mount in situ hybridization for TSHβ mRNA. Thyrotroph distribution within the cephalic lobe was heterogeneous among embryos, but most commonly extended from the ventral medial region to the dorsal lateral regions, along the boundary of the cephalic and caudal lobes. Inhibition of endogenous thyroid hormone production with methi-mazole (MMI) decreased plasma thyroxine (T4) levels and increased pituitary TSHβ mRNA levels on e19 and d1. However, control pituitaries contained significantly more TSHβ peptide than MMI-treated pituitaries on e17 and e19, suggesting higher TSH secretion into the blood in MMI-treated groups. We conclude that thyrotroph abundance and TSH production increase prior to hatching, that thyrotrophs are localized heterogenenously within the cephalic lobe of the anterior pituitary at that time, and that TSH gene expression and secretion are under negative feedback regulation from thyroid hormones during this critical period of development.

SIGNIFICANCE OF TRIIODOTHYRONINE FOR THYROID HORMONE SUPPLY DURING STIMULATION

1966 ◽  
Vol 53 (1) ◽  
pp. 151-161 ◽  
Author(s):  
Dieter Emrich ◽  
Peter Pfannenstiel ◽  
Günter Hoffmann ◽  
Walter Keiderling
Keyword(s):  
Thyroid Hormone ◽  
Thyroid Hormones ◽  
Thyroid Function ◽  
Hormone Production ◽  
Partial Inhibition

ABSTRACT The metabolism of the two thyroid hormones thyroxine (T4) and triiodothyronine (T3) and particularly the T4/T3 ratio was studied by the 131I technique in rats and rabbits during stimulation. Both exogenous TSH and experimentally increased endogenous TSH (secondary to the partial inhibition of thyroid function by sodiumperchlorate) caused a change in the T4/T3 ratio in favour of T3. This response of thyroid hormone production (in rats) and secretion (in rabbits) was found at different times after the use of 131I. It depended on the intensity of the direct or indirect thyrotrophic stimulation. From this observation it is suggested that the synthesis and the secretion of the biologically more effective T3 is more markedly increased during stimulation than is T4 probably in order to compensate more successfully for deficiencies in the peripheral thyroid hormone supply.

scholarly journals Thyroid hormone receptor beta sumoylation is required for thyrotropin regulation and thyroid hormone production

JCI Insight ◽  
2021 ◽  
Author(s):  
Sujie Ke ◽  
Yan-Yun Liu ◽  
Rajendiran Karthikarj ◽  
Kurunthanchalam Kannan ◽  
Jingjing Jiang ◽  
...  
Keyword(s):  
Thyroid Hormone ◽  
Hormone Receptor ◽  
Thyroid Hormone Receptor ◽  
Hormone Production ◽  
Receptor Beta
Sign in / Sign up

Export Citation Format

Share Document