Responses of Adrenal Corticosteroid Secretion to Hypotension and Hypovolemia *

Abstract

Secretion rates of 17-hydroxycorticosteroids were measured in dogs with chronic adrenal venous cannulas before and after various hemodynamic manipulations. Both hemorrhage and hypotension produced by ganglionic blockage consistently stimulated secretion of corticosteroids. Prevention of hypotension by concomitant administration of norepinephrine prevented the response to ganglionic blockage but not that to hemorrhage. Reinfusion of shed blood in hemorrhaged animals and restoration of blood pressure in animals with blockade led to rapid return of secretion of corticosteroids to control levels. Bilateral carotid constriction did not affect secretion of corticosteroids, but the response was small and delayed. This response was prevented by prior bilateral nephrectomy, but nephrectomy did not alter the responses to hemorrhage or to hypotension. It is concluded that hypotension alone is an effective stimulus to secretion of corticosteroids, but hypovolemia stimulates secretion of corticosteroids even in the absence of hypotension. The mechanisms mediating adrenal activation in response to these stimuli have not been defined by the present studies.