Adipose Tissue Lipolysis in Golden Hamsters with Chronic Hypoglycemia and Hyperinsulinemia Due to a Transplantable Islet Cell Tumor[*]

Abstract

Golden hamsters bearing a transplantable islet cell tumor had high plasma immunoreactive insulin (IRI) and low blood glucose concentrations. Certain aspects of the lipid metabolism were studied in these animals. No correlation was found between blood glucose, plasma IRI and plasma free fatty acid (FFA). In vitro, the epididymal adipose tissue of tumor-bearing hamsters released more glycerol than that of control hamsters, but since the re-esterification of FFA was also increased, the net FFA release was lower than that of normal animals. At a glucose concentration of 100 mg%, glucose uptake and glycerol release were higher and the FFA release was lower than at a glucose concentration of 25 mg%. Prostaglandin E₁ (PGE₁), at concentrations of 1 or 5 µg/ml, reduced glycerol release by the adipose tissue of normal fasted or fed hamsters, but had no effect on the glycerol release of fasted, hypoglycemic tumor-bearing animals. The relative influence of hypoglycemia, hyperinsulinism and endogenous lipolytic factors is discussed. The specific causes of the accelerated lipolysis in the presence of the insulinoma remains unknown.

Key words

Lipolysis - Golden Hamster - Hypoglycemia - Transplantable Islet Cell Tumor - Blood Glucose - Serum Immunoreactive Insulin - Serum FFA - Epididymal Adipose Tissue - PGE₁

1 Presented in part at the Autumn Meeting of the British Diabetic Association, Aberdeen, 27-28 Sept. 1968 and published in abstract form in Diabetologia 5: 201 (1969).

1 Presented in part at the Autumn Meeting of the British Diabetic Association, Aberdeen, 27-28 Sept. 1968 and published in abstract form in Diabetologia 5: 201 (1969).