Inhibitory effect of vitamin D3 on 3'methyl-4-dimethyl-amino-azobenzene-induced rat hepatocarcinogenesis: a study on antioxidant defense enzymes.

The anticarcinogenic effect of vitamin D3 (VD3) on 3,-methyl-4-dimethyl-amino-azobenzene (3,-Met-DAB)-induced hepatocarcinogenesis was investigated in male Sprague-Dawley rats. Anticancer efficacy of VD3 was estimated using different possible biomarkers, namely reduced glutathione (GSH) concentration, gamma-glutamyl transpeptidase (GGT) activity, glutathione S-transferase (GST) activity, glutathione reductase (GRd) activity, glutathione peroxidase (GPx) activity in hyperplastic nodules (HNs) and non-nodular surrounding parenchyma (NNSP) liver areas. VD3 was found to control the carcinogen-induced alterations in GSH level, GST, GGT, GRd and GPx activity both in HNs and NNSP liver areas during long-term exposure. A decrease in the number of HNs was also evident in the present investigation. VD3 was proved to be an effective antitumor drug during the initiation/promotion phases of hepatic carcinogenesis but the effect was found to be less prominent during initiation and promotion phases.