title: Effect of Casein and Soy Protein Isolate on Vitamin B(6) Nutritional Status in Rats.
abstract: Two experiments were conducted to test the effect of casein and soy protein isolate (SPI) on the nutritional status of vitamin B(6) in rats. Adult Long-Evans rats were fed with a casein or SPI diet at a 40% protein level with (control) or without (B(6)-deficient) 7 mg of pyridoxine/kg diet. Vitamin-B(6)-deficient rats were depleted of B(6) with (experiment 1) or without (experiment 2) deoxypyridoxine. In experiment 1, each rat was loaded with 150 mg of DL-tryptophan after 5 weeks of pair feeding. The rats on the vitamin-B(6)-deficient SPI diet (SPI-B(6)) excreted twice the amount of urine xanthurenic acid in 24 h than did the rats on the vitamin-B(6)-deficient casein (casein-B(6)) diet (p < 0.05). In experiment 2, L-tryptophan was loaded in a 20-mg dose at the end of each week. The excretion of xanthurenic acid was higher in the SPI-B(6) group than in the casein-B(6) group over the 5-week period of the experiment (p < 0.05). Erythrocyte transaminase (EGOT and EGPT) activities were lower, while EGOT and EGPT indexes were higher in the SPI-B(6) group than in the casein-B(6) group (p < 0.05). The results suggest that the source of dietary protein significantly influenced the status of B(6) nutrition in these rats. Copyright 1997 S. Karger AG, Basel
authors.affiliation: Department of Biochemistry, College of Medicine, National Taiwan University, Taipei, Taiwan.
authors.forename: S.-C.
authors.initials: SC
authors.lastname: Lu
authors.forename: P.-C.
authors.initials: PC
authors.lastname: Huang