[Metabolism and toxicity of various xenobiotics in vitamin B1 deficiency and after administration of thiamine and thiamine diphosphate].

Metabolism of aminopyrine, sodium benzoate and toxicity of cyclophosphamide were studied in 185 male rats under conditions of various content of vitamin B1 in the animals. Deficiency of thiamin led to an increase in excretion of 4-aminoantipyrine and especially of its acetylated derivative. After administration of thiamin metabolism of aminopyrine was not distinctly altered, while thiamin diphosphate inhibited the drug biotransformation. In deficiency of vitamin B1 transformation of benzoic acid into hippuric acid was inhibited but formation of glucuronides was elevated. Administration of thiamin or thiamin diphosphate stimulated the benzoic acid conjugation and inhibited the glucuronides formation. Deficiency of vitamin B1 accelerated the cyclophosphamide toxicity. Preadministration of thiamin and especially of thiamin diphosphate decreased the toxic effect of cyclophosphamide.