[Insulin--a regulator of exocrine pancreas function?].

The following is a review of the literature concerning experimental data on insulin effects in the exocrine pancreas and a discussion whether those experimental data give prove to an important role of insulin in the regulation of the exocrine pancreatic function. Morphological features of an endocrine/exocrine relationship like a special vascularisation and periinsular "halos", a hypertrophy of acini adjacent to the islets of Langerhans, are described. Next the characteristics of the insulin receptor of exocrine pancreatic acini and its regulation by insulin, so called "up- and downregulation", are discussed. This is followed by a description of the exocrine pancreatic function in type I diabetes of humans and in experimental insulin deficiency diabetes of rats. Short term effects of insulin on the exocrine pancreas in vitro, using isolated pancreatic acini, like stimulation of glucose- and aminoacid uptake, stimulation of proteinsynthesis, phosphorylation of certain proteins and stimulation of CCK induced amylase release are discussed. Next potential long term effects of insulin on the exocrine pancreas in vivo like regulation of the synthesis of certain digestive enzymes are described, followed by a discussion of long term insulin effects in vitro employing AR42J cells, a rat pancreatic carcinoma acinar in origin. Additionally the insulin like growth factors and their unknown role in the exocrine pancreas are mentioned.