Obesity and pancreatic islet hyperplasia in the Mongolian gerbil.

Abstract

In a colony of Mongolian gerbils maintained on a standard laboratory diet, occasional obese animals were found. Obesity developed in animals of both sexes and was either transitory or permanent. The mean fasting blood glucose level in non-obese and obese gerbils was 83 and 105mg/100 ml, respectively. Glucosuria and hyperglycemia were found only in a few obese animals, whereas the glucose tolerance was decreased in most obese gerbils. — The endocrine pancreas of the obese animals was morphologically either normal or more often hyperplastic, sometimes with the appearance of adenomatous islets. Theβ-cells possessed prominent Golgi complex and endoplasmic reticulum, and sparse granulation. Large, granule-poor, cells and mitotic figures were seen in the islets. Degenerative changes occurred in theβ-cells of diabetic animals. — It is suggested that the maintenance of the gerbils under laboratory conditions with free access to laboratory diet plays a major role in the development of obesity and that the endocrine pancreas of these animals has a good capacity for hyperplasia that often is sufficient to maintain normo-glycemia in obese animals, although the glucose tolerance is decreased.