[The biphasic response of hepatic arterial blood flow caused by vasoactive substances--an experimental study in dogs]

In ten male mongrel dogs, blood flow was measured in the common hepatic artery (CHA), portal vein (PV) and liver tissue before and after the injection of vasoactive substances: angiotensin II (1.0 micrograms/kg), prostaglandin F2 alpha (1.0 micrograms/kg) and vasopressin (0.1 Unit/kg), under observation of the systemic circulation. Each injection caused a biphasic response in CHA blood flow, an initial decrease followed by a marked increase, while PV blood flow decreased. Liver tissue blood flow was reduced just after injection, but soon returned to a normal level. The duration of action was the shortest with prostaglandin F2 alpha and the longest with vasopressin. In using vasoactive substances in pharmaco-angiography, it is important to consider the biphasic response in CHA blood flow as well as the duration of action of these substances.