THE ROLE OF GLUCOCORTICOID ACTIVITY IN THE INHERITANCE OF HYPERTENSION - STUDIES IN THE RAT

Young (3-week-old) spontaneously hypertensive rats (SHR) had significa ntly higher basal plasma corticosterone levels than WKY rats and maxim um responses to ACTH were also higher. In isolated adrenocortical cell s from these rats, corticosterone production was also more responsive to ACTH in SHR. There was no significant difference in aldosterone pro duction. Mononuclear leucocytes from older (10-week-old) SHR had a hig her affinity for dexamethasone but a smaller number of binding sites p er cell. The SHR therefore has higher circulating glucocorticoid level s and the target cells have a higher apparent affinity for this agonis t. However, the target cells also have a smaller binding capacity. The precise resultant effect of these changes on glucocorticoid activity will require additional studies on specific glucocorticoid-dependent v ariables.