ON THE QUESTION OF THE ORIGIN OF URINARY AMMONIA

Abstract

A few years ago we (1) presented evidence in favor of the view that urinary ammonia is formed by the kidney and that acid is not neutralized by ammonia during transportation in the blood. In subsequent communications (2) we discussed later experimental findings of others bearing on the question of the origin of urinary ammonia. During the past 2 years further work has appeared which is more or less directly related to this question and we feel that a discussion of some of these recent findings is desirable. Embden (3) and Parnas and Mozolowski (4) have studied am- monia formation in muscle tissue in relation to contraction, and later Embden and his collaborators reported extensive studies along this line (5). Recently Bliss (6-8) has reported work related to the problem of the origin of urinary ammonia. Bliss has frankly adopted our view that the traces of ammonia found in the blood are of no significance in connection with the neutralization of acids in the body. Obviously this view involves acceptance of the theory that the urinary ammonia has its origin in the kidney. Bliss has presented evidence from which he con- cludes that the amide nitrogen fraction in blood protein is subject to quantitative variation under certain definite conditions. As a result of this work and the further finding that the kidney possesses an enzyme capable of liberating ammonia from the amide nitrogen of the blood proteins, Bliss draws the inference that this amide nitrogen fraction is closely related to the process of neutralization of acids in the tissues, or at least to the neutralization of lactic acid in muscle, and to the ammonia which is found in the urine.