Oral administration of urea cycle intermediates in lysinuric protein intolerance: effect on plasma and urinary arginine and ornithine.

In lysinuric protein intolerance, an autosomal recessive disorder of amino acid transport, oral citrulline increases the plasma concentration of urea cycle intermediates more than does oral arginine or ornithine. The clinical improvement suggests that citrulline affords the best means of correcting the ornithinopenic malfunction of the urea cycle.