Adrenocortical Responsiveness to ACTH and Angiotensin II in Hypophysectomized Dogs and Dogs Treated with Large Doses of Glucocorticoids1

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Abstract
In dogs hypophysectomized 4 weeks previously, and in dogs treated for 30 days with large doses of glucocorticoids, the increments in 17-hydroxycorticoid and aldosterone secretion produced by graded doses of ACTH and angiotensin n were determined. In both groups of dogs, neither ACTH nor angiotensin II stimulated 17-hydroxycorticoid secretion. In the chronically hypophysectomized dogs, neither hormone had a marked stimulatory effect on aldosterone secretion, but in the steroid-treated dogs the increments in aldosterone secretion produced by angiotensin II and ACTH were not significantly different from those in untreated control dogs. This suggests that deficiency of some pituitary factor other than ACTH was responsible for the decreased increments in aldosterone secretion in the chronically hypophysectomized dogs. The data also suggest that there are 2 separate secretory systems in the adrenal, one secreting 17-hydroxycorticoids and the other secreting aldosterone.