ACTION OF INSULIN ON BIOSYNTHESIS OF AMYLASE AND SOME OTHER ENZYMES OF RAT PANCREAS

A single inejction of alloxan induces in the rat, within a few days, a 10-fold decrease of the level and of the rate of biosynthesis of pancreatic amylase. Both are quickly restored to normal values by daily injections of insulin. Biosynthesis rates were calculated from the rate of [14C]valine incorporation into the pure enzyme. Special care was taken in evaluating, as precisely as possible, the specific radioactivity of valine in the free amino acid pool of pancreas. In spite of this finding, insulin does not appear to control the biosynthesis of pancreatic amylase in a direct way. When injected into normal rats fed on a starch-poor diet, it fails to increase the level of the enzyme. The effect of diabetes and insulin on other pancreatic enzymes, such as chymotrypsinogen and lipase, is weaker and probably more complex. © 1968.