Practical prospects for the therapeutic use of essential amino acid analogues.

Interest in essential amino acid analogues developed as a means of diverting ammonia nitrogen into protein synthesis in patients with chronic renal failure, urea cycle enzyme defects and hepatic failure. Long-term practical therapeutic value has so far only been proved in children with urea cycle defects. Recent work confirms that the alpha-keto acid of leucine in particular alters protein turnover and may prove of wide practical application to improve nitrogen balance in post-operative patients and others with severe illness.