Glucocorticoid receptor gene expression in the exocrine and endocrine rat pancreas

Although pleiotropic effects of glucocorticoids on the endocrine and exocrine pancreas are well documented, it remains controversial whether these effects are due to direct interactions of glucocorticoid hormones with their receptors in the respective target cells. We therefore examined gene expression of the glucocorticoid receptor (GR) in various functional compartments of the rat pancreas. Using in situ hybridization by generating a radioactive cRNA probe from a specific cDNA clone for the rat glucocorticoid receptor we found a gradient in the expression of receptor mRNA transcripts from endocrine > acinar > ductal cells. In contrast, no specific hybridization signal was observed in the endothelial cells of vascular structures. Using a monospecific polyclonal antibody against the rat glucocorticoid receptor in Western blot analyses we found significant expression of the 94 kD receptor protein in an enriched pancreatic acinar cell preparation. This data suggest that rat pancreatic exocrine cells might serve a direct target tissue for glucocorticoid action.