Metabolism of Insulin-I¹³¹ in the Extrahepatic Tissues

¹ From the Scripps Clinic and Research Foundation, La Jolla, and the Department of Physiology, School of Medicine, University of Southern California, Los Angeles, California

Insulin-I¹³¹ is rapidly degraded after injection in the intact animal. The process is also rapid in the eviscerated animal with kidneys. Degradation is relatively slow in the eviscerated-nephrectomized preparation, so that it can be used to study the manner of distribution of injected insulin-I¹³¹. It takes about an hour for this compound to become evenly distributed in the body and then it appears to be contained within the extracellular compartment. In the eviscerated animal biological activity of injected insulin-I¹³¹ parallels the concentration of the compound in the plasma except during the 1st hour while it is still passing from plasma to tissue fluid.