Renin suppression by DOC and NaCl in the rat.

PETTINGER, WILLIAM A., MARY MARCHELLE, AND LORAINE A~GUSTO. Renin suppression by DOC and NaCl in the rat. Am. J. Physiol. 221(4) : 1071-1074. 197 1 .-Endocrine and dietary changes known to alter plasma renin activity (PRA) were studied in the nonanesthetized rat. Deoxycorticosterone (DOC) suppressed PRA by 90-95%. Ingestion of a low-sodium diet elevated PRA from a mean control value of 120 to 530 rig/l 00 ml per hr. This elevation was diminished or reversed by increments of sodium in the drinking water. Thus, changes in PRA in the rat are qualitatively similar to those in other species. Sodium pentobarbital and ether anesthesia increased PRA to levels similar to anesthesia control values reported by other investigators using these agents in their standard experimental procedure. Thus, normal levels (approximately 100 ng/lOO ml per hr) of PRA in the unanesthetized rat appear to be much lower than reported in the anesthetized rat. Ether and sodium pentobarbital anesthesia also abolished the depression of PRA induced by administration of DOC and sodium. This artifactual elevation of plasma renin, and thus angiotensin, activity by anesthetic agents can explain: I) the previously reported failure of DOC to suppress renin activity in the rat (9), and 2) the limited aldosterone secretory response to angiotensin in the anesthetized rat. These results suggest that the nonanesthetized rat is a good subject for physiologic and pharmacologic studies of the renin-angiotensin system.