The effects of streptozotocin (STZ)-induced diabetes on induction of hepatic preneoplastic lesions by diethylnitrosamine (DEN) were investigated in male Fischer rats. A single dose of STZ was injected intravenously either 2 weeks before or after initiation with DEN. The blood glucose levels were significantly elevated from 1 week after STZ-injection until autopsy. The numbers of GST-P positive foci at 1 week after DEN administration in the STZ-injected rats were similar to those in the non-diabetic rats. In contrast, both the numbers and areas of GST-P positive foci > 2 mm in diameter 8 weeks after DEN administration were increased significantly in the rats treated with STZ after DEN exposure compared with the non-diabetic control rats. The results suggest that hepatic preneoplastic lesions initiated with DEN are promoted by STZ treatment-inducing diabetes.
Keywords: GST-P positive foci; diabetes; diethylnitrosamine; hepatocarcinogenesis; liver; streptozotocin.