Circulatory regulation in anuric rats: anuria and haemorrhagic hypotension.

In rats made anuric by ureteral ligation or by creating a bladder-caval venous shunt, cardiac index increased and total peripheral resistance decreased proportionally to the change in the serum NPN level. Circulating blood and plasma volume did not change. In ureteral-ligated or bladder-caval venous-shunted rats, cardiac output and its organ fractions were determined by SAPIRSTEIN'S technique. In the ureteral-ligated animals, vasoconstriction in the kidneys, and vasodilation in the skin were found. After bladder-caval shunt, vasodilatation developed in the myocardium, gut, skin and carcass. After ureteral ligation, posthaemorrhagic shifting decreased mainly the renal flow, while after a bladder-caval venous shunt, mainly the renal and intestinal flows.