Abstract

Dimethylnitrosamine (DMV)-induced renal mesenchymal preneoplastic loci and hepatic glutath- ione S-transferase P (GST-P) gene expression in weanling F344 male rats were used as early carcinogenic biomarkers to evaluate anticarcinogenicity of Copolang. Continuous daily intake of 0. 85 1.1 g Copolangiday/kg b. wt. for 3 weeks immediately following a single intraperitoneal administration of DMN (15, 30 and 60 mg/kg body weight) significantly blocked these DMN-induced biomarkers. The dose response slopes for DMN with or without Copolang treatment (1% Copolang in drinking water) were 0.27 and 0,47, respectively. Copolang treatment significantly inhibited DMN-induced small renal mesechymal cell proliferation, Likewise hepatic GST-P enzyme expression in the lowest DMN dose group (15 mg/kg) and the highest dose (60 mg/kg) was blocked nearly completely. In the highest dose group, multicellular GST-P enzyme loci were not observed in this experimental group, however, there was GST-P positive single cells were observed. On the other hand, in the middle dose group, GST-P histochemical staining was much more diffuse and not as intense. The results of this study demonstrate that Copolang treatment significantly inhibits expression of DMN-induced early carcinogenic biomarkers. A long term whole animal carcinogenic bioassay study is necessary to confirm anticarcinogenic activtiy of Copolang.