The Absorption of Glycine and d,1-Alanine.

Abstract

The rate of intestinal absorption of glycine and alanine has been studied with the method described in a previous publication. 1 Groups of 10 rats were killed 1, 2 and 3 hours after feeding a 15 per cent solution of the amino acid by stomach tube. The average absorption coefficients (i. e., the amount absorbed per 100 gm. of body weight per hr.) for glycine were as follows: 1 hr., 0.048 gm.; 2 hours, 0.050 gm.; 3 hours, 0.046 gm. The values obtained for d, 1-alanine were: 1 hour, 0.044 gm.; 2 hours, 0.044 gm.; 3 hours, 0.047 gm. If these values are plotted against time, it will be found that they fall on a straight line. Since the rate of absorption of different hexoses and pentoses was also found to follow a straight line, 1 the same considerations that were made with respect to the sugars, apply to the amino acids. The rate of absorption is, within wide limits, independent of the absolute amount and the concentration of amino acid present in the intestine. If this were not the case, the rate of absorption would be represented by a curve rather than a straight line.

A mixture of equal parts of glycine and alanine was absorbed at a rate of 0.061 gm. per 100 gm. of body weight per hour. One would expect a rate of absorption of 0.09 gm., if each amino acid was absorbed independently from the mixture. It has been found previously, 2 that when glucose and galactose are absorbed from a mixture, the rate of absorption of both sugars is reduced to such an extent that the total amount of sugar absorbed is not much greater than if glucose alone or galactose alone were being absorbed.