Pancreatic polypeptide causes diarrhea and weight loss in obese mice but not in lean littermates.

Pancreatic polypeptide was infused into obese-hyperglycemic (ob/ob) mice and lean littermates to determine its effect on weight gain. Obese mice continuously infused with 30, 60, or 100 micrograms/day for 7 days developed both diarrhea and weight loss in a dose dependent fashion. Lean littermates infused with 100 micrograms/day developed neither diarrhea nor weight loss. Light microscopic study of ileum and colon revealed no abnormalities. These studies indicate that the effects of pancreatic polypeptide are in part genetically determined since the obese and non-obese mice differ at only one gene locus.