Taurine levels in blood and urine of vitamin B6-deficient and estrogen-treated rats.

The objects of the present study were to determine whether a L-methionine or a L-cysteine test-load was more effective in evaluating the effects of estrogen on vitamin B6 deficiency in rats, and to determine whether urine or blood was the better test fluid to measure taurine levels. In animals fed a vitamin B6-supplemented diet, urinary excretion of taurine was twofold higher after administration of a L-cysteine test-load compared to a L-methionine test-load. Greater percentage reductions in the quantity of excreted taurine were observed in the vitamin B6-deficient rats when L-cysteine was utilized as the test-load than when L-methionine (2 mmole) was utilized. Treatment with estrogen demonstrated no significant differences in urinary taurine excretion. Vitamin B6 deficiency without estrogen treatment raised the levels of taurine in the blood of the animals treated with a L-methionine test-load. No changes in the blood taurine levels were observed in the animals administered a L-cysteine test-load.