Studies in Amino Acid Utilization

Abstract

Quantitative requirements for the 9 amino acids indispensable for maintenance of weight, appetite and nitrogen equilibrium of the adult well-nourished male albino rat have been measured. The measurements were made under a standardized set of conditions, including adequate caloric, vitamin and mineral intakes. Total nitrogen intake was more than sufficient to supply the maintenance needs of the animals. The level of the amino acid under consideration was varied, while all other factors of the diet were maintained constant. Weight changes and nitrogen balance were determined. The minimum quantity of each amino acid necessary to maintain nitrogen equilibrium and weight balance was estimated from the curves relating amino acid intake to nitrogen balance or weight change, respectively. From the data presented the following conclusions were drawn: