Pyridoxine-5'-beta-D-glucoside: metabolic utilization in rats during pregnancy and availability to the fetus.

Pyridoxine-5'-beta-D-glucoside (PNG), which is abundant in various plant-derived food products, has been shown to be poorly utilized in male rats and adult men. To assess the metabolic utilization of PNG during pregnancy and the availability to the fetus, [3H]PNG and [14C]pyridoxine (PN) were orally administered to 15-d pregnant rats for direct assessment of the intestinal absorption, tissue distribution, and urinary excretion of the radioisotopes. The level of 3H was significantly greater in the liver, and urinary excretion of 3H tended to be lower than that of 14C. The relative distribution of 3H among the groups of B-6 vitamers within the liver was similar to that for 14C. There was greater uptake by the fetus of 3H than of 14C. There was no difference in the relative concentrations of 3H and 14C among the groups of B-6 vitamers within the fetus. Results of this study suggest that the metabolic utilization of PNG is similar to that of PN during pregnancy. Therefore, the availability of vitamin B-6 derived from maternal PNG seems to be similar to that of vitamin B-6 derived from maternal PN.