THE INACTIVATION OF INSULIN BY LIVER SLICES OF THE RAT1

Abstract

The insulin-inactivating activity (insulinase) of slices of liver is much less than that of homogenates or extracts of equivalent amts. of liver. Insulinase activity is related directly to the quantity of liver slices employed and to the length of incubation. In the presence of an inhibitor extracted from liver (insulinase-inhibitor), the insulinase activity of liver slices is markedly reduced. Whereas fasting results in a diminution in the insulinase activity of homogenates and extracts of liver, slices of liver from fasted rats tend to have an increased activity. It is proposed that the insulin-inactivating capacity of liver slices is dependent upon the balance of insulinase and insulinase-inhibitor activities, and that with fasting there is a greater reduction in the inhibitor than in the iasulinase. The phenomenon of "starvation diabetes" may be attributed in part at least to a relative increase in insulinase activity.