Effects of CCK on Gene Expression of Endocrine Pancreatic Hormones

Abstract

Regulation of endocrine pancreatic hormone gene expression by cholecystokinin (CCK) was examined in the rat using cloned cDNA probes to quantify changes in specific mRNAs (insulin, glucagon, pancreatic polypeptide and somatostatin). Plasma CCK levels were raised to concentrations comparable to physiologic postprandial values either by including soybean trypsin inhibitor (SBTI) in the intraduodenal perfusate of an elemental diet (6.9 +/- 1.0 pM, n = 6), or by intravenous infusion of CCK-8 (6.0 +/- 0.9 pM, n = 6). SBTI infusion for 48 h resulted in a three- to fourfold increase in procarboxypeptidase B and kallikrein mRNA levels. Similar increases were observed when CCK was infused intravenously for 24 h. In contrast, neither SBTI intraduodenally, nor intravenous CCK had any effects on mRNA levels of insulin, glucagon, PP or somatostatin. These data therefore indicate that CCK at physiologic postprandial plasma concentrations stimulates pancreatic protease gene expression but has no effects on gene expression of endocrine pancreatic hormones.