Destruction of I131 Labeled Insulin by Liver Slices.

Insulin labeled with I131 was used to determine the effect of liver slices on the degradation of insulin. 2. The insulin-inactivating activity of slices of rat liver (insulinase) is associated with a degradation of I131 insulin. 3. The degradation of I131 insulin by liver slices follows first order kinetics and is related directly to the quantity of liver slices employed. 4. A non-protein fraction of liver (insulinase-inhibitor) which inhibits the action of insulinase also inhibits the degradation of I131 insulin by liver slices.