Concerning the Origin of Glycuronic Acid.

Abstract

Recently considerable work has been done in order to determine the probable source of glycuronic acid in the animal body. Some authors contend that glycuronic acid is an intermediary product of glucose catabolism while others believe that it is an unusual product of glucose metabolism produced only under the strain required for the detoxication of some aromatic or aliphatic substance. Other experimenters think that it is derived from the catabolism of exogenous or endogenous protein material, since 58.5% of protein material is convertible into glucose. Quick found that fasting dogs, fed on benzoic acid, excrete large amounts of the glycuronic acid conjugate, and that depancreatized dogs form glycuronic acid with a decrease in urinary sugar. The excretion of benzoyl glycuronic acid is accompanied by increased endogenous catabolism. These facts indicate that glycuronic acid is made more readily from glycogenetic amino acids than from glucose itself. Using rabbits, the effect of various amino acids on glycuronic acid formation was tried. The rabbits were fed a week on carrots and a little lettuce. Then total nitrogens (Kjeldahl) and glycuronic acids (Quick's method) were determined. The experiment was divided into three parts. During the first period, menthol was fed while giving a diet of lettuce and carrots. Then food was taken away and menthol only was given, and in the last period menthol and an amino acid were fed. Two grams of menthol as a warm water suspension was administered daily through a stomach tube. The amino acids in the third period were fed in 1 or 2 bgm. closes on alternate days in conjunction with the menthol suspension. The urine was collected without catheterization in 24 hour periods, and total nitrogens and glycuronic acids were determined.