Reversal of diabetes by the isotransplantation of nicotinamide-streptozotocin-induced islet adenoma in rats

The effect of syngeneic transplantation of islet tumors induced by streptozotocin-nicotinamide treatment into Fisher inbred diabetic rats was studied. Transplantation of 10 mg of tumor tissue under the kidney capsule of severely diabetic animals resulted in complete amelioration in 9 of 14 animals. Partial improvement was noted in three animals, whereas only one animal showed no change in diabetic condition within 4 months. Improvement in diabetes was accompanied by gain in body weight, decrease in blood sugar level and urinary glucose excretion, and normalization of glucose tolerance. After removal of the kidney containing the tumor grafts, the animals reverted to a severe diabetic condition, suggesting that the tumor graft supplied the insulin needs of the diabetic animals. The graft tissue exhibited in vitro insulin synthesis and secretion in response to 16.7 mM glucose.