The incorporation of ammonia nitrogen into albumin in man: the effects of diet, uremia and growth hormone.

15 N-ammonium chloride was given orally to 17 individuals in 20 studies. Retention of 15N by those with normal renal function was inversely proportional to the protein intake; enrichment of albumin with 15N increased during protein restriction. Protein restriction appeared to be a more potent stimulus to the synthetic use of ammonia than a large pool of urea nitrogen. Both retention of isotope and enrichment of albumin decreased when a high protein diet was given. Enrichment of albumin with 15N in response to 10 or 20 mg of growth hormone daily was similar to that in healthy individuals on a 20 g protein diet for 3 weeks. The relevance of these findings to the nutritional potential of recycled urea nitrogen is discussed.