Failure of L-carnitine to protect mice against ammonia toxicity.

Recent reports indicate that intraperitoneal administration of L-carnitine protects mice from ammonia toxicity. We found that mice injected with L-carnitine and subsequently challenged with ammonium acetate succumb as readily as mice injected with saline and the ammonium acetate. Mice pretreated with L-carnitine exhibited higher levels of liver ammonia than the saline-pretreated control mice. The ammonia and urea levels in serum and brains were similar in two groups. Our findings are in contrast to those reported previously and therefore warrants further investigation before L-carnitine can be considered as a drug to alleviate hyperammonemia in humans.