[Reactivity of the adrenal cortex and the renin-angiotensin system in young rats with spontaneous hypertension].

Corticosteroid biosynthesis from 14C-progesterone by the adrenal glands in vitro, 14C-aldosterone metabolism by the liver, plasma aldosterone content, and also angiotensin I concentration and blood plasma renin activity were studied in Okamoto rats with spontaneous hypertension and in Wistar rats with normal blood pressure, 4--5 weeks of age. Acute immobilization stress induced in rats with normal blood pressure caused activation of the adrenal cortex glucocorticoid function without increase of aldosterone biosynthesis or of its blood content, whereas in rats with hypertension the same stress led to adrenal cortex mineralocorticoid function activation and to the sharp blood plasma aldosterone elevation. In rats with normal blood pressure there is a reduction of renin activity and an increase in the angiotensin I content during stress, whereas in rats with hypertension the activity of the renin-angiotensin system remains unchanged. An increase in the mineralocorticoid concentration in rats with spontaneous hypertension can play an important role under these conditions in the elevation of arterial pressure.