1. The influence of two intravenous vasopressors (angiotensin II and norepinephrine) on renal function and intrarenal blood flow distribution was studied in thirteen cirrhotic subjects and the results compared with those from eight non-cirrhotics.
2. Increased sodium excretion occurred in four of eight cirrhotics with ascites who received comparable pressor doses of angiotensin II and one of five similar subjects who received norepinephrine. In contrast, sodium excretion fell or remained the same in all eight non-cirrhotics.
3. Renal plasma flow fell and filtration fraction rose in nearly all subjects who did not respond to vasopressors with a natriuresis but changed little in those who did.
4. Vasopressor-induced changes of the multicompartmental 133xenon washout curve were qualitatively different in the group who responded with a natriuresis in comparison to the others. Whereas the distribution of flow to the fastest component fell in the non-responder, it remained the same or rose in those who developed a natriuresis.
5. We interpret these results as suggesting a state of relative renal vasopressor resistance allowing the induced systemic hypertension to reduce tubular sodium reabsorption in some cirrhotics by influencing peritubular ‘physical factors’.