Inhibition of insulin release by synthetic rat C-peptide II in isolated rat islets.

The effect of synthetic rat C-peptide on glucose-induced insulin release was studied in isolated islets of rat pancreas. Addition of rat C-peptide II to the medium inhibited glucose-induced insulin release from islets by 30 to 40 percent. Rat C-peptide I, human connecting peptide and bovine, porcine and canine C-peptides had no significant effects on insulin release from islets of rat pancreas.