Effect of hyperammonemia on the levels of carnitine in mice.

Decreased carnitine levels have been noted in conditions of hyperammonemia. We have measured carnitine and its derivatives in acute and sustained hyperammonemia in mice and studied the effect of carnitine administration thereon. Sustained hyperammonemia decreased carnitine in liver and muscle. Acetylcarnitine was decreased in liver and muscle in both acute and sustained hyperammonemia but increased in brain. Long-chain acylcarnitines decreased in brain and muscle in acute hyperammonemia and in liver and muscle is sustained ammonia intoxication. Intraperitoneal administration of carnitine increased the levels of free carnitine and acyl derivatives, especially in liver, but sustained hyperammonemia significantly affected the distribution of exogenous carnitine. The importance of these findings relative to the alterations of lipid metabolism observed in Reye's syndrome and inherited hyperammonemias, as well their implication in the protective effect of carnitine on hyperammonemia, are discussed.