Induction of gamma GT- and GST-P positive foci in the liver of rats treated with 2-nitropropane or propane 2-nitronate.

2-Nitropropane (2-NP) or its anionic form propane 2-nitronate (P2-N) were tested as initiators in a sequential model of rat hepatocarcinogenesis, at the end of which preneoplastic foci were histologically detected. Six intraperitoneal (i.p.) injections of 25, 50 or 100 mg 2-NP or P2-N/kg body weight resulted in the appearance of liver gamma-glutamyltranspeptidase (gamma GT)- and glutathione S-transferase (GST-P)-positive foci, whose number and size increased with the dose of initiator. 2-NP and P2-N were equally effective. The potency of the highest dose (6 x 100 mg/kg body wt) was comparable to that of a single injection of diethylnitrosamine (100 or 200 mg/kg body wt). This work provides a short-term (70 days) and convenient model for further studies on 2-NP carcinogenicity.