To evaluate the effects of prostaglandin E₁ (PGE₁) on the hepatic circulation in cholestasis, hepatic arterial blood flow (HAF), portal venous blood flow (PVF), cardiac output, and heart rate during PGE₁ infusions were investigated before and 2 weeks after biliary obstruction in conscious dogs by a transit-time ultrasonic flowmeter. In the control period, HAF and PVF increased dose dependently with the infusion of PGE₁ from 0.05 to 0.5 µg/kg/min. During the biliary obstruction period, a lower dose of PGE₁ increased HAF and PVF. The plasma concentration level of PGE₁ during the infusion of PGE₁ was significantly higher at each dose in the cholestatic animals. These results suggest that the metabolism of PGE₁ is attenuated by cholestasis. Plasma PGE₁ concentrations should be useful in deciding the optimal dose of PGE₁.

This study was conducted to examine how the effects of dopamine and dobutamine on hepatic blood flow were influenced by obstructive jaundice in a conscious canine model. Prior to biliary obstruction, portal venous blood flow (PVF) increased in response to the infusion of either dopamine or dobutamine: dopamine infused at 8 micrograms/kg per min produced an increase of 19 +/- 0% in PVF, while dobutamine infused at 16 micrograms/kg per min produced an increase of 30 +/- 2%. Although hepatic arterial blood flow (HAF) decreased dose-dependently in response to the infusion of dopamine, no significant change was observed in HAF in response to any dose of dobutamine. Obstructive jaundice attenuated or completely abolished the PVF-increasing effect of dopamine, whereas it did not significantly alter the effect of dobutamine on hepatic blood flow. In dogs with obstructive jaundice, dopamine at 16 micrograms/kg per min produced a decrease of 17 +/- 3% in PVF. These findings suggest that dobutamine is more effective than dopamine for increasing hepatic blood flow in patients with obstructive jaundice.

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