Transplantation of insulinoma into the diabetic Syrian hamster.

Syrian hamsters were rendered diabetic with intraperitoneal streptozotocin and were maintained in the diabetic state for a minimum of 14 days. A hamster islet cell tumor was transplanted subcutaneously with a prompt return of water intake (38 +/- 9.1 ml/day to 7.1 +/- 2.2 ml/day, mean +/- SD), urine glucose (4.8 +/- 0.84 g/day to less than 250 mg/day), urine output (37.4 +/- 10.9 ml/day to 7.6 +/- 2.1 ml/day), blood glucose (297 +/- 31.9 mg/dl to 87.6 +/- 28 mg/dl), and weight gain (1.0 to 0.8 g/day) to normal control levels. Histologic examination of the engrafted tumors revealed a well encapsulated tumor with no evidence of metastatic disease. The transplanted insulinomas maintained well differentiated histologic features without evidence of necrosis. Immunopathologic studies failed to reveal any evidence of either humoral or cell mediated immunity directed toward the allograft. Each animal was successfully transplanted with a 1 mm tumor explant. A single rodent tumor donor provided adequate material for engraftment for five recipients. The transplanted insulinomas maintained full functional and enzymatic capabilities. Similar studies utilizing the hamster insulinoma engrafted into the athymic nude mouse showed amelioration of the same diabetic symptomatology. Many of the technical difficulties encountered with whole organ and isolated islet transplantation encourages development of a more practical model. These experimental results suggest an alternative method for supplying the diabetic with an endogenous insulin source.