Plasma amino acids in hyperphagic pups subjected to a glucose gavage.

An oral gavage of either glucose or saline was given to pups fed either standard diet or cafeteria diet. The plasma amino acid concentrations were measured by a radiochemical method. In the standard diet group, plasma Asn+Asp, Thr, Pro, Cit, Trp and Phe levels were higher in rats receiving a glucose solution than in those given saline solution; taurine (on day 20) and Ser (on day 30) showed also higher plasma values. Plasma Arg and taurine levels in rats receiving glucose were lower than those in rats receiving saline when these pups were fed the cafeteria diet. Tyr (on day 20) and Gly and Pro (on day 30), showed decreased plasma values. The diet consumed during the days preceding a glucose gavage may have pronounced effects on several metabolites, particularly on nitrogen metabolism. The homeostasis of plasma amino acids was held highly constant in spite of the variety of diets supplied, indicating a remarkable homeostatic capacity on amino acidemia against dietetic manipulation.