Circulatory effects of somatostatin in anaesthetized dogs

Five anaesthetized dogs were given 20 infusions of 1--9 min duration of somatostatin in a dosage of 0.2--15 micrograms.kg-1.min-1. Cardiac output was measured by thermodilution. Electromagnetic blood flow measurements were simultaneously performed in the hepatic artery proper, the left gastric artery, the superior pancreatico-duodenal artery, the superior mesenteric artery and in the portal vein. Mean arterial blood pressure was recorded continuously. Somatostatin reduced all splanchnic blood flows measured by 15--35%, except for the hepatic artery flow, which was increased by 5% or unaffected. Cardiac output and mean arterial pressure were unchanged. Somatostatin was thus demonstrated to exert a specific vasoactivity in the splanchnic area without influencing central circulation. It is suggested that somatostatin acts directly on the vascular smooth muscle.