Metabolic effects of prostaglandin E1 have been previously demonstrated in cirrhosis, apparently independent of changes in large splanchnic vessel hemodynamics. The effects of prostaglandin E1 on functional liver blood flow were tested by measuring the extrarenal clearance of D-sorbitol in six controls and eight patients with cirrhosis during systemic superinfusion of saline or prostaglandin E1 (30 microg/hr), in random order. Doppler ultrasonography of systemic and splanchnic circulation was also performed before the test and at the end of the two study periods. Prostaglandin E1 infusion increased femoral blood flow by nearly 60% in controls and over 30% in cirrhosis, without any effect on mean arterial pressure and heart rate. Mesenteric artery and portal blood flow were unchanged, as were Doppler-measured resistance indices in the liver, spleen and kidney. Sorbitol-assessed functional hepatic flow was 30% lower in cirrhosis, and did not change systematically during prostaglandin E1 infusion. We conclude that prostaglandin E1, at doses able to elicit metabolic effects and changes in systemic hemodynamics, does not affect splanchnic blood flow and/or hepatic microcirculation in normal subjects and in portal-hypertensive patients with cirrhosis.