Differences in adrenal cholesterol, ascorbic acid, circulating corticosterone and aldosterone during the onset of hypertension in SHR vs WKy rats

Young adult male spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto rats were killed under strictly quiescent conditions when they became 24, 32, 44, 60, 90 and 120 days of age. Systolic blood pressure was measured just prior to autopsy. Adrenal glands were assayed for ascorbic acid and total cholesterol content, and examined histologically. At 60 days of age, the blood pressure of the SHR became abnormally elevated, reaching severely elevated levels by 120 days of age. The adrenal glands of SHR were consistently smaller than those of WKy but their zonae glomerulosae stained intensively positive for lipid. Adrenocortical ascorbate and cholesterol content remained consistently and significantly lower in SHR vs WKy as did circulating corticosterone levels. Plasma aldosterone levels rose concomitantly with rising blood pressure in SHR and became progressively lower with age in normotensive WKy. These findings suggest that corticosteroidogenesis is different in SHR vs normotensive WKy rats.