Streptozotocin, a N-nitrosomethylamide, was given to highly inbred Lewis rats. Six months later all the animals remained chronically diabetic but none had evidence of renal tumors. At this time kidneys were transplanted from diabetic donors into normal, unilaterally nephrectomized recipients, and 4 of 11 of these transplanted kidneys developed renal tumors within the next 4 months. Kidneys transplanted from normal donors into diabetic or normal recipients did not develop tumors. However, 3 of 10 diabetic rats receiving kidneys from normal donors developed tumors in their own remaining kidneys. Six months following streptozotocin administration, the diabetic state of 9 animals was reversed by pancreatic tissue transplantation. Four of these animals developed renal tumors within 6 months of cure of their diabetic state. These studies suggest that streptozotocin-induced renal tumors in rats are due to the direct effect of the inducing agent on the kidney rather than to the diabetic state and have important implications for future studies of the immunology of carcinogenesis.
Aided by Grants HL 06314, AM 12375, and AI 10704 from the NIH, and by the Twin Cities Diabetes Association, the Minnesota Medical Foundation, and the Graduate School of the University of Minnesota.