GLUCAGON RELEASE FROM THE PANCREAS OF THE NEWBORN RAT

Abstract

SUMMARY A solid phase radioimmunoassay for glucagon was specially modified in order to overcome the problems involved in the measurement of glucagon release from incubated pieces of pancreas. The modified immunoassay procedure was used to study glucagon release from pieces of pancreas taken from newborn rats aged from 1 to 20 days. The glucagon content of rat pancreas was also measured during this period. It was found that glucagon release from rat pancreas was stimulated by arginine and inhibited by octanoic acid at 1 and 2 days of age. However, glucagon release at 3 days of age was low, and between 3 and 7 days of age glucagon release could not be inhibited by octanoic acid or stimulated by arginine. At 10 and 20 days of age, the stimulatory action of arginine and the inhibitory action of octanoic acid were again noted. Glucagon release, measured at several ages, was not significantly affected by changes in glucose concentration. The glucagon content of the rat pancreas rose to a maximum at 5 days of age and then decreased gradually over a period of 90 days. It is suggested that the low rate of glucagon release between 3 and 7 days of age may be a result of the high levels of blood fatty acids and ketone bodies found in the rat during this period.