Abstract
The rôle of the thyroid gland in the hypertrophy of the adrenal cortex following administration of anterior pituitary substance has been a subject of considerable investigation with reports that are conflicting. Some experimenters 1 , 2 , 3 have concluded that this hypertrophy of the adrenal cortex is mediated largely or entirely through the thyroid gland. Others 4 5 6 7 8 have found that the presence of the thyroid gland is not necessary for this reaction. In view of these conflicting reports we carried out similar experiments on the guinea pig.
Twenty-three young guinea pigs of both sexes were used in 2 series of experiments. In the first there were 12 animals (6 males and 6 females) ranging in age at the beginning of injections from 28 to 34 days, and in weight from 213 to 364 g. Four were thyroidectomized, 3 gonadectomized, 3 thyroidectomized and gonadectomized, and 2 unoperated. Gonadectomy was performed 11 days before, and thyroidectomy 7 days after, beginning injections. All animals received daily intraperitoneal injections of anterior pituitary extract for 48 days, and were sacrificed 2 to 5 days after the last injection. In the second experiment there were 11 guinea pigs (6 males and 5 females) ranging in age at the beginning of injections from 32 to 38 days, and in weight from 251 to 380 g. Litter-mate pairs of the same sex were chosen, one of each pair being thyroidectomized 8 days before beginning treatment. All animals received daily intraperitoneal injections of anterior pituitary extract, and were sacrificed in pairs after 7, 8, 9, 19 and 20 days. The extract used was a 0.5% acetic acid extract of dried beef anterior pituitary prepared, with slight modifications, according to the method of Loeb, and concentrated so that one cc was equivalent to 0.1 to 0.5 g of dried gland.
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