Drug metabolism in experimental tuberculosis: II. Modification of monooxygenase activities due to infection by the administration of isonicotinic acid hydrazide.

Isonicotinic acid hydrazide (INH) upon administration to tuberculous guinea pigs exhibited curative effect by bringing back the tissue weights to normal. The reduced hepatic content of cytochrome P450 and NADPH-cytochrome C reductase activity of tuberculous guinea-pigs was restored to normal by INH treatment. Also a similar effect of INH was observed in the case of aminopyrine-N-demethylase and benzphetamine-N-demethylase in the liver and lung of tuberculous guinea-pigs. But INH had little effect on the content of cytochrome b5 and NADH-cytochrome b5 reductase activity. The hepatic and pulmonary activities of glutathione-S-transferase exhibited a tendency to come back to normal while UDP-glucuronyl transferase was unaffected by INH administration to the infected animals. The results suggest that the treatment of tuberculous guinea-pigs with INH cause the normalisation of disturbed hepatic and pulmonary metabolism.