Prevention of isoniazid tumorigenicity by antitoxicants of isoniazid in Swiss mice.

Effect of isoniazid on blood ammonia levels and protein biosynthesis in tissues of Swiss mice was studied. Isoniazid treatment resulted in an elevation of the blood ammonia. It inhibited the protein biosynthesis in lung and kidney tissues of Swiss mice after 24 h of treatment. Simultaneous administration of L-arginine or L-sodium glutamate or pyridoxine hydrochloride or folic acid prevented the inhibition. Further, effect of these antitoxicants of isoniazid was studied on its tumorigenicity. Mice were fed isoniazid (1.1 mg/mouse/day) and the antitoxicant (1.1 mg/mouse/day) and killed when they appeared moribund. Incidence of tumor in mice receiving L-arginine or L-sodium glutamate along with isoniazid did not show any significant difference when compared with the mice treated with isoniazid alone. On the other hand, observations with folic acid gave full protection against tumorigenic action of isoniazid while pyridoxine hydrochloride displayed partial protection.