Evidence of Hypothalamic Control of the Pituitary Release of Thyrotrophin.

Abstract

Bilateral, symmetrical, electrolytic lesions in the hypothalamus between the suprachiasmatic and caudal ventromedian nuclei prevented the goitrogenic response of the rat to thiouracil feeding. The iodide-concentrating capacity of the thyroid, however, increased to approx. the same extent as that of intact rats similarly treated. It appears that hypothalamic lesions of this type impair the secretion of thyrotropin by the pituitary. It is not known whether this interference with thyrotropin secretion is qualitative or quantitative, nor whether hypothalamic control is exerted by neural or hormonal mechanisms. The available evidence points to the secretion of a hypothalamic hormone, however.