title: Studies on the effects of isoniazid on acetylhydrazine metabolism in vivo and in vitro.
abstract: The interaction of isoniazid with its hepatotoxic metabolite acetylhydrazine has been studied. In vitro, isoniazid at a concentration of 0.5 mM was found to inhibit the microsomal metabolism of acetylhydrazine to a reactive acylating species. In vivo, however, coadministered isoniazid inhibited the acetylation to diacetylhydrazine and concomitantly increased the microsomal metabolism of 14C-acetylhydrazine to a reactive intermediate which covalently bound to liver macromolecules. Comparison of urinary metabolites of isoniazid at two dose levels indicated that acetylation of acetylhydrazine produced as a metabolite may be inhibited by the parent drug.
mesh_terms: D000107:Acetylation; D000818:Animals; D002245:Carbon Dioxide / Q000378:metabolism; D006834:Hydrazines / Q000378:metabolism* / Q000652:urine; D066298:In Vitro Techniques; D007538:Isoniazid / Q000378:metabolism / Q000494:pharmacology*; D008297:Male; D051381:Rats
chemical_list: D006834:Hydrazines; D002245:Carbon Dioxide; D007538:Isoniazid