Intestinal Hormones and Insulin Release: In Vitro Studies using Rabbit Pancreas

Abstract

The in vitro rabbit pancreas preparation of Coore and Randle has been used to study the effect of glucagon, secretin, pancreozymin and an extract of porcine duodeno-jejunal mucosa (DJE) on glucose induced insulin release in vitro. Only glucagon and DJE potentiated glucose induced insulin release. The existence is suggested, of a previously unidentified intestinal hormone, "incretin" contained in DJE.

The effects of I-leucine, I-arginine and I-lysine on insulin release were studied, and only leucine was found to give significant stimulation of insulin release.

Glucagon, D J E and pancreozymin were found to potentiate leucine induced insulin release, while secretin had no effect.

D-Mannoheptulose was shown to inhibit insulin secretion by glucagon and DJE in the presence of high glucose levels, but not to inhibit the release of insulin by leucine or its potentiation by glucagon, DJE and pancreozymin. The implications of these findings with respect to the insulin secretory response to oral glucose and amino acids, and to the mode of action of intestinal hormones on the B cell are discussed.

Key words

Insulin Secretion in Vitro - Incubation of Pancreas - Intestinal Hormones - Amino Acids