Dietary taurine alters ascorbic acid metabolism in rats fed diets containing polychlorinated biphenyls

The effect of dietary taurine on ascorbic acid metabolism and hepatic drug- metabolizing enzymes was investigated in rats fed diets containing polychlo rinated biphenyls (PCB) to determine whether taurine has an adaptive and pr otective function in xenobiotic-treated animals. Young male Wistar rats (60 g) were fed diets containing 0 or 0.2 g/kg diet PCB with or without 30 g/k g diet of taurine for 14 d. The rats fed the PCB-containing diets had great er liver weight, higher ascorbic acid concentrations in the liver and splee n and greater hepatic cytochrome P-450 contents than control rats that were not treated with PCB (P < 0.01). In PCB-fed rats, urinary ascorbic acid ex cretion was enhanced, and serum cholesterol concentration (especially HDL-c holesterol) was significantly elevated compared with those in control rats. Dietary taurine significantly potentiated the increases in the urinary exc retion of ascorbic acid and the rise in the levels of cytochrome P-450 whic h were caused by PCB treatment. On the other hand, the supplementation of t aurine to control diet did not alter these variables. Taurine may enhance t he hepatic drug-metabolizing systems, leading to the stimulation of the asc orbic acid metabolism in rats fed diets containing PCB.