Cardiac output (CO), renal blood flow (RBF) and hepatic blood flow (HBF) were measured by the microsphere method before (control) and at 4 and 10 h after the induction of acute renal failure by intramuscular injection of glycerol in water-drinking, long-term saline-drinking and long-term captopril (converting enzyme inhibitor)-drinking rats. At 4 h after glycerol injection, CO, RBF and HBF significantly decreased in all three groups. At 10 h after glycerol injection, CO, RBF and HBF recovered to 88% of the respective control levels in only the saline-drinking rats, whereas CO, RBF and HBF further decreased to 53, 38 and 58% of the control levels, respectively in the captopril-drinking rats. At this time, not only acute renal failure but also hepatic disorder developed in the water-drinking and captopril-drinking rats as indicated by elevations of serum creatinine, urea nitrogen, alanine aminotransferase and other blood chemistry levels. The development of acute renal failure was not suppressed by captopril, but by long-term saline load. Thus, we conclude that the decrease in CO is an important variable of the early decrease in renal and hepatic perfusion in glycerol-induced acute renal failure, and that the early recovery of HBF as well as RBF may play an important role in preventing the development of acute renal failure.