Selective enhancement of glutathione S-transferase activity in liver and extrahepatic tissues of rat following oral administration of vanadate.

The effect of oral administration of vanadate (100, 200 and 400 nM for 30 days) on the activity of the detoxifying enzyme system glutathione S-transferase (GST) in rat liver and in several extrahepatic tissues was examined. Vanadate showed a high activity as GST inducer in liver and in small intestine mucosa followed by large intestine mucosa and kidney in a dose-dependent manner. No significant alterations in GST activity were observed in forestomach and lung tissues after vanadate. Vanadate treatment that resulted in an enhancement of GST activity impaired neither hepatic nor renal function as evidenced by serum glutamic oxaloacetic transaminase, glutamic pyruvic transaminase, sorbitol dehydrogenase, urea, and creatinine. Since the ability to induce an increase of detoxifying enzyme activity by anticarcinogenic agents was found to correlate with their activity in the inhibition of tumorigenesis, the trace element vanadium might be considered a potential cancer chemopreventive agent.