Pancreatic polypeptide, glucagon and insulin secretion from the isolated perfused canine pancreas

The release of pancreatic polypeptide (PP) by gut hormones, acetyl choline and adrenaline was investigated in an isolated perfused pancreas preparation. PP was potently released by 1 nmol/l caerulein (186±12%, p<0.001) and gastric inhibitory peptide (GIP) (211±31%, p<0.005) as well as by 1 [νmol/l acetyl choline (1097±59%, p<0.001). A significant two-fold release of PP was also evoked by 1 nmol/l vasoactive intestinal peptide (VIP) (129±38%, p<0.02 and gastrin (108±25% p<0.01). Insulin release, induced by high glucose concentration was enhanced by both GIP (210 ±38%, p<(0.01) and VIP (48±5%, p<0.001). In addition GIP enhanced the release of glucagon by 179±18% (p<0.001) at 1.4 mmol/l glucose and by 127±24% (p<0.005) at 8.3 mmol/l glucose. Thus no simple inter-relationship appears to exist between the control of the three circulating islet hormones.