Effect of a somatostatin analogue (SMS 201-995) on hemodynamics and glucagon secretion in cirrhotic rats.

The effects of somatostatin analogue, SMS 201-995, on systemic and splanchnic hemodynamics and glucagon secretion were investigated in control and cirrhotic rats induced by thioacetamide administration. Hemodynamics were measured using the radioactive microsphere method. Immunoreactive glucagon (IRG) was determined in the portal vein and femoral artery and the splanchnic output (OP) of IRG was calculated. In control rats, SMS 201-995 induced a decrease of 5.6% in portal venous inflow and a 25.8% decrease in OP of IRG. In cirrhotic rats, SMS 201-995 produced a 14% decrease in portal pressure, a 13.6% decrease in portal venous inflow, and a 57.8% decrease in OP of IRG. In systemic hemodynamics no significant changes were noted following SMS 201-995 administration in the control or cirrhotic rats. The ratio of cirrhotic rats to the controls in the rate of decrease in portal venous inflow was similar to that in the percentage of decrease in OP of IRG. We conclude that SMS 201-995 is useful for the treatment of portal hypertension because of its effect of reducing portal pressure with mild changes in systemic hemodynamics. We suspect that the decrease in portal venous inflow by SMS 201-995 is mainly due to a reduction in the release of glucagon, a vasodilatory gastrointestinal hormone.