Abstract
A 48-year-old man who showed a regular diurnal fluctuation of blood ammonia level was diagnosed as adult-type citrullinemia with quantitative estimation of plasma amino acids and urea cycle enzymes in the liver. The restriction of daily protein intake less than 50g and oral administration of lactulose had no effect on blood ammonia level. The efficacy of four amino acid solutions which had been used in order to improve the hepatic encephalopathy was compared each other in this case. Glutamate-arginine mixture had the same effect as glutamate solution in lowering blood ammonia level, and glutamate was thought to be essential. Also, oral administration of citrate showed a remarkable effect almost comparable to intravenous administration of glutamate. Analysis of plasma amino acids three hours later after citrate ingestion demonstrated an increase in glutamate and a decrease in citrulline. These observation may suggest that a metabolic pathway of citrate-α-ketoglutarateglutamate-glutamine, takes part in disposing free ammonia in the blood.
