Abstract

The effect of varying hepatic blood flow on the hepatic removal rate of oxyphenbutazone was studied in 12 anesthetized dogs. Hepatic blood flow was manipulated by creating a systemic artery to splenic vein shunt which was regulated by a perfusion pump. Hepatic blood flow was measured by placing electromagnetic flowmeter probes on the celiac and superior mesenteric arteries and within the shunt circuit. There was a positive relationship between hepatic blood flow and the hepatic removal rate of oxyphenbutazone. An inverse curvilinear relationship between hepatic blood flow and the hepatic extraction of oxyphenbutazone was found. The extraction ratio was independent of the blood concentration of oxyphenbutazone. We conclude that hepatic blood flow is a significant determinant of the disposition of oxyphenbutazone and presumably other drugs as well.