Organic acidaemia and Hyperammonaemia: review.

Recent clinical and experimental evidence on the effects of organic acids in producing or ameliorating hyperammonaemia is reviewed. The importance of hepatic mitochondrial N-acetylglutamate and its precursors, glutamate and acetyl-CoA, in the control of ureagenesis and thus blood ammonia levels is emphasized by recent work. The hypothesis is proposed that protein loads stimulated urea cycle activity via glutamate-induced changes in N-acetylglutamate concentration, while the effects of organic acids on ureagenesis are related in a predictable way to their effects on hepatic concentrations of acetyl-CoA.