Role of the renin-angiotensin system in the control of vasopressin and ACTH secretion during the development of renal hypertension in dogs.

Experiments were performed to determine if the activation of the renin-angiotensin system that occurs during the development of two-kidney, one clip Goldblatt hypertension in dogs is accompanied by increases in vasopressin and adrenocorticotrophic hormone (ACTH) secretion. Following renal artery constriction, there were marked increases in arterial blood pressure, plasma renin activity (PRA), and plasma angiotensin II (AII) concentration. These changes were accompanied by an increase in plasma vasopressin concentration during the second week following constriction, and there were significant correlations between plasma vasopressin concentration and PRA (r = 0.57, p less than 0.001), and between plasma vasopressin concentration and plasma AII concentration (r = 0.59, p less than 0.001). In contrast, plasma corticosteroid concentration, used as an index of changes in ACTH secretion, did not change significantly. Acute blockade of the renin-angiotensin system with captopril or saralasin produced the expected changes in blood pressure, PRA, and plasma AII concentration but did not decrease plasma vasopressin or corticosteroid concentrations. These results indicate that during the development of renal hypertension in dogs, there may be an interaction between the renin-angiotensin system and vasopressin, but not between the renin-angiotensin system and the pituitary-adrenal axis. They also show that the antihypertensive action of captopril in this experimental model is not mediated via suppression of vasopressin, ACTH, or corticosteroid secretion.