Long-term reversal of streptozotocin-induced diabetes in rats by intramuscular islet implantation.

The ability of pancreatic islets implanted into abdominal muscle to effect a recovery from streptozotocin-induced diabetes was compared with that of i.p implants. Pancreases from 17 to 35 Lewis neonates were cultured for 6 days and placed in i.m. or i.p. sites in severely diabetic Lewis rats. Body weight, food and water intakes, urinary output, and 4-hr fasted plasma glucose levels returned to normal in both groups. Neither plasma insulin and glucose responses to intravenous glucose tolerance tests nor plasma glucose responses to oral glucose tolerance tests differed among i.m. or i.p. implant recipients and normal, age-matched controls, even after 1 week's prior challenge of insulin secretory capacity by a high sucrose diet. Plasma glucose levels were reduced after oral administration of tolbutamide in the three groups. Plasma glucagon of i.m. and i.p. implant recipients after a 4-hr fast or after an oral load of arginine were not significantly different from those of controls, although levels tended to be higher in the implant groups. Neither i.m. nor i.p. implant groups reverted to the diabetic state in the 10 months following pancreatic implantation. These findings validate the long-term efficacy of intramuscular implantation of cultured islets in reversing diabetes in inbred rats.