[Age and features of the functional activity of the thyroid gland in experimental hypocorticism]

Data are presented on age peculiarities of the functional activity of the thyroid gland, thyrotropic function of the hypophysis, transport forms of thyroid hormones, and tissue thyroxin saturation in experimental hypocorticism in rats. Investigations were conducted on albino male rats of three age groups--1 1/2-2, 8-10, 28-32 months old. The changes which took place in rats of different age after adrenalectomy were in the same direction, but unequal in different links of the thyroid gland regulation of metabolism and its function. These changes were expressed in reduction of the thyrotropic function of the hypophysis, of the secretory activity of the thyroid gland, of the thyroxin-binding capacity of the blood serum, and of the tissue thyroxin saturation. With the advance of age there was a marked decrease in the reaction capacities of the functional link of the hypophysis and the thyroid gland tissue, but not in the tissues.