EFFECT OF VITAMIN-B6 STATUS OF THE LACTATING RAT ON TAURINE BIOSYNTHESIS AND AVAILABILITY TO THE SUCKLING PUP

Pregnant rats were fed either a vitamin B-6 adequate (20 mg/kg diet) or deficient diet throughout gestation and 10 days postpartum. After this time period, all dams were gavaged [S-35]cysteine and [H-3]taurine and pups were allowed to nurse. Milk and tissues of the dams and pups were collected 24 and 48 hours after gavage. Dams fed the diet depleted of vitamin B-6 were deficient of the vitamin asassessed by plasma pyridoxal 5'-phosphate concentration. There wasno difference between the two dietary groups in the level of [H-3]taurine in the heart or liver of the lactating dam,however, there was a significant reduction in the S-35/H-3 taurine ratio in the liver of the dams fed the deficient diet. No dietary difference was observed in the level of [H-3]taurine in the pup's stomach contents or S-35/H-3 taurine in the dam's milk. No difference was observed in the level of [H-3]taurine present in the heart, liver or brain of the pups fed the two diets, although, there was a significant reduction in the isotopic ratio in liver of pups fed the deficient diet. Based on these observations, a vitamin B-6 deficiency of the lactating dam resulted in reduced biosynthesis of taurine in the dam and pup without influencing the availability of endogenous or exogenous taurine in milk.