Inhibition of the renin-angiotensin system by pinealectomy in female rats.

The influence of the pineal gland on the renin-angiotensin system has been studied in female rats. Pinealectomy produces a decreased plasma renin activity (PRA) concomitant with an increased corticosterone level, and with no changes in plasma aldosterone. Administration of indol melatonin reverses the effects of pinealectomy. On the other hand ovariectomy induces an increased PRA while decreasing corticosterone and aldosterone levels. However when pinealectomy and ovariectomy are both performed, neither PRA nor corticosterone changes. These results suggest that the pineal gland may exert an influence on the renin-angiotensin system via adrenal and/or ovarian pathways.