THE HYPOGLYCAEMIC ACTION OF SOMATOSTATIN IN THE ANAESTHETIZED DOG

Abstract

The hypoglycemic action of somatostatin was investigated in fasted anesthetized dogs. An isotopic turnover technique with radioactive D-[2-3H]glucose tracer was used to measure rates of hepatic production and peripheral utilization of glucose before, during and after a 60 min infusion of 150 .mu.g somatostatin. Plasma concentrations of insulin, glucagon, growth hormone, cortisol and free fatty acids were also measured. Somatostatin infusion decreased plasma glucose demonstrable within 10 min. After 60 min plasma glucose had fallen to 75% of the pre-infusion concentration. Simultaneously the specific activity of the D-[2-3H]glucose increased, and calculation of the rates of production and utilization of glucose over 10 min intervals indicated that the mean hepatic production rate of glucose fell to 59% of the pre-infusion rate, while the rate of peripheral utilization of glucose fell to 83% of the pre-infusion rate. The hypoglycemic action of i.v. somatostatin depends exclusively on the inhibition of hepatic glucose production. This effect may have been partly due to a fall of plasma glucagon concentration and occurred despite a fall of plasma insulin to less than 1 mu-1.