Degradation of insulin and proinsulin in the normal state and in experimental diabetes.

1. Homogenates of various organs and tissues of the rat decompose insulin to different degrees. 2. Proinsulin, taken in amounts equimolar to insulin, are decomposed in the same period of time by homogenates of different organs and tissues of the rat, to a substantially lesser degree than insulin. 3. Alloxan diabetes leads to a pronounced decrease in the ability of homogenates of all the tissues studied to break down both insulin and proinsulin.