In vivo and in vitro Effect of Glucagon on DL-Leucine-1-C 14 Incorporation Into Protein of Rat Pancreas. ∗

Abstract

Summary

In vivo studies measuring DL-leucine-1-C¹⁴ incorporation into pancreatic protein helped confirm earlier histological and chemical observations that glucagon administration to rats and rabbits inhibited synthesis of pancreatic protein. In vitro studies revealed that glucagon had no direct effect on DL-leucine-1-C¹⁴ incorporation into protein of segments of rat pancreas. Incubation of pancreas in medium with lowered essential amino acid levels or in serum from glucagon-treated rats with lowered amino acid levels resulted in decreased incorporation of radioactive leucine into pancreatic protein. Neither lowering non-essential amino acids nor adding glucagon to incubation medium had any effect. It was suggested that glucagon administration in vivo causes a decrease in protein synthesis of the pancreas and that this action of glucagon is secondary to the lowering of essential amino acid levels in the serum.