Pancreatic polypeptide and other hormones in pancreas of obese (ob/ob) mice.

The insulin, glucagon, somatostatin and pancreatic polypeptide content of acid-ethanol extracts of pancreas from lean and obese (ob/ob) mice of various ages was determined by radioimmunoassay. Rat and mouse pancreatic polypeptide react weakly with antibodies to avian, bovine and canine pancreatic polypeptide, but immunoassay for this peptide was possible using an antibody to the carboxyl-terminal hexapeptide of bovine pancreatic polypeptide and amino-terminal labelled bovine pancreatic polypeptide as tracer. The insulin, glucagon and pancreatic polypeptide content of pancreas from obese mice was greater than that of lean controls. The increase in insulin content uniformly involved ventral, dorsal and splenic lobes. Glucagon content was elevated primarily in the splenic lobe. Pancreatic polypeptide content was most significantly elevated in the splenic lobe where pancreatic polypeptide cells are infrequent in normal lean mice and this was accompanied by increased numbers of pancreatic polypeptide cells per islet in this lobe.