Adrenal renin-angiotensin-aldosterone system in streptozotocin-diabetic rats.

Previous studies have indicated that the local renin-angiotensin system (RAS) plays an important role in the regulation of aldosterone release. We focused this study on examining the dissociating changes in circulating RAS and adrenal RAS, and we produced a low plasma renin status in streptozotocin (STZ)-induced diabetic rats. Four and six weeks after treatment with STZ, the rats showed hyperglycemia, hyporeninemia, decrease in plasma angiotensin II (AII), and a slight, but non-significant increase in plasma aldosterone in the rats. The adrenal renin activity and aldosterone concentration were significantly increased in the group of rats six weeks after induction of diabetes compared to those in control rats. The group of rats four weeks after induction of diabetes showed an increase in adrenal aldosterone concentration and a slight, but non-significant increase in adrenal renin activity. Plasma ACTH, serum sodium, and potassium were unchanged in both treatment groups compared to the control. The present results indicate that hyperactivity or residual activity of adrenal RAS under hyporeninemia is associated with severe diabetes mellitus.