Effect of Hemorrhage-induced Hypotension on Adrenocortical Responsiveness to Adrenocorticotrophin

Hypophysectomized dogs were used to study the effect of hemorrhage-induced hypotension upon the responsiveness of the adrenal cortex to adrenocorticotrophin (ACTH). Adrenal venous blood samples were collected under sodium pentobarbital anesthesia and were analyzed for 17-hydroxycorticosteroids (17-OHCS). ACTH was infused intravenously throughout each experiment. A sustained rise in adrenal 17-OHCS secretion was produced. Marked falls in arterial blood pressure and adrenal blood flow were induced by a removal of 20-25ml/kg of arterial blood. The rate of adrenal 17-OHCS secretion was decreased to the level of 28-65% of the pre-hemorrhage secretion rate.