Effect of age and role of kidneys and liver on thyrotropin turnover in man

Hypothyroidism as a Late Sequela in Patients with Graves' Disease Treated with Antithyroid Agents

“…A B S T R A C T In 1971, thyroid function was evaluated in 15 unselected patients whose only therapy for diffuse toxic goiter was a course of thionamide drug treatment completed [20][21][22][23][24][25][26][27] By the time a second major follow-up study was completed in 1978, two additional patients had become frankly hypothyroid. A third subject met accepted criteria for subclinical hypothyroidism.…”

Amniotic fluid thyrotropin (TSH) following maternal administration of thyrotropin releasing hormone

“…In the adult, TSH has a biological half life of 50 -60 minutes and is mainly metabolized by the kidney. Moreover, immunoreactive TSH is not found in the urine [5].…”

Influence of Age and Sex in Modulating TSH Level in Primary Hypothyroidism

“…Several studies have examined the effect of age and sex on the hypothalamic-pituitary-thyrotrophs axis by analyzing the TSH response to TRH injection [1][2][3][4][5][6][7][8][9][10][12][13][14][15][16][17] or to inhibitors of peripheral T 3 production. 11 Although the results were conflicting, most studies showed a diminished TSH response in the elderly and in males.…”

“…The latter can be due to decreased responsiveness of the hypothalamus and/or the thyrotrophs to hypothyroidism. Our study did not address these different possibilities; however, the observation that TSH response to TRH may be decreased in the elderly, [1][2][3][4][5][6][7][8][9][10] and that the metabolic clearance rate of TSH in rats is decreased rather than increased by aging, 18 localizes the defect to the thyrotrophs. Finally, our patients had severe primary hypothyroidism (TSH ≥30 mU/L) and were on thyroxine therapy before the hypothyroid episodes.…”

“…Ann Saudi Med 1995;15 (6) An age-related diminution in thyrotrophs function has been found by most, but not all, investigators. In response to an injection of a bolus of thyrotropin-releasing hormone (TRH), a decrease in thyroid-stimulating hormone (TSH) release was shown in elderly males and females, [1][2][3] in elderly males, 4 in elderly females, 5 and in elderly males but not in elderly females. [6][7][8][9][10] Further, the expected increase in TSH level in response to the inhibition of T 4 deiodination by oral iopanoic acid was not observed in healthy elderly volunteers.…”