The etiology of the decrease in renal peripheral benzodiazepine receptor (PBR) binding caused by stress was studied in rats. Prior investigations suggest that the response of the renal PBR to stress occurs independently of the hypothalamo-pituitary-adrenal (HPA) axis and sympathetic nervous system. The present experiments tested the hypothesis that the renin-angiotensin system is involved in regulating the PBR. Eighty min of brief, intermittent tailshocks caused increases in plasma renin activity and decreases in renal PBR binding. The stress-induced decrease in renal PBR binding was reversed by pretreatment with captopril. Acute administration of angiotensin II (ANG II) alone caused reductions in PBR binding in kidney, heart, and cerebral cortex. These data suggest that ANG II may be an endogenous factor responsible for regulating the PBR in several tissues during stress.