The effects of caerulein on insulin secretion in anaesthetized dogs

Abstract

1 . Insulin concentration changes in pancreatico-duodenal venous plasma were studied in anaesthetized dogs injected with caerulein. 2 . Rises in insulin concentration were elicited by rapid intravenous injection of caerulein, as well as by intravenous infusion. Threshold doses were 10 ng/kg and 0·5–1 (ng/kg)/min respectively. 3 . At the highest dose used (500 ng/kg by rapid intravenous injection and (25 ng/kg)/min by intravenous infusion) the increase in immuno-reactive insulin release was approximately 7 to 9 times the base levels. 4 . Adrenalectomy potentiated the effects of intravenous infusion of caerulein. 5 . On a molar basis, caerulein was 2–3 times as active as pancreozymin. 6 . It is concluded that caerulein is a potent stimulant of pancreatic islets in the dog and that it may be considered as a model peptide, capable of being substituted for pancreozymin in any experiment. 7 . The mechanism of the insulin stimulating effect of caerulein is discussed. The possibility of a direct “β-cytotropic” effect of the peptide is suggested.