THE EFFECTS OF THE RATE OF ADMINISTRATION OF AMINO ACID PREPARATIONS ON URINARY WASTAGE OF AMINO ACID NITROGEN IN MAN

Abstract

A comparison was made in 15 human subjects of the urinary loss of amino acid N in a 4 hr. period following the admn. of 3 different amino acid prepns. each containing 5.4 g. N. In addition, in 5 of these patients the urinary amino acid N was determined for the same period after an infusion of physiological saline. The injns. of the protein hydrolysates here given at rates which previous experience had shown to approach the max. tolerated rate in the majority of the patients. The greatest urinary wastage of amino acid N occurred with the amino acid solns. prepared by the enzymatic hydrolysis of casein, a prepn. containing large amts. of peptide N. The increased loss of total amino acid N which followed the use of this digest appeared to be due mainly to "bound" amino acid N, since the loss of free amino acid N was of the same magnitude as with the other prepns. tested. The % of the total administered amino acid N lost in the urine in a 4 hr. period following the enzmic hydrolysate of casein was 1.6 to 19.7 %. Under similar conditions, usually 3 to 5% of the total amino acid N was found in the urine after the admn. of either an acid hydroiysate of casein or a mixture of amino acids. In contrast, there was little free amino acid N lost after the admn. of any of the prepns. studied regardless of the speed of infusion. Mixtures of amino acids, if well tolerated, can be given at exceedingly rapid rates without causing increased spillage into the urine.