Studies on the Metabolism of Glucuronic Acid in the Dog

Abstract

Since glucuronic acid and glucosamine are characteristic constituents of the prosthetic group of mucin, the biochemical synthesis of mucin can not take place without them. Very little is known about the metabolism of these substances, except that they are probably not glycogenic and are surprisingly inert in the body. We are interested in studying the metabolism of these substances because their metabolism is so closely related to the metabolism of mucin and gastro-intestinal function. We wish to report our findings to date. When dogs are fed borneol, it is excreted as borneol glucuronic acid. In another paper of this series, Miller and Conner show that the glucuronic acid arising from the digestion of mucin in rabbits is readily available for conjugation with menthol, and that either the rabbit is unable to synthesize glucuronic acid from carbohydrates or amino acid metabolites, or that the synthesis takes place slowly. We were interested in determining if this applied to dogs. Three dogs having an average weight of 9.5 kg. were fed a stock diet of bread and corn meal gruel containing a little meat broth. They were given 5 gm. of borneol in 90 cc. of 1% agar by stomach tube for 31 successive days. Their average total excretion of glucuronic acid as borneol glucuronic acid was 30.78 gm. Their average daily excretion of glucuronic acid was 1.11. gm. At the end of the experiment their average weight was 8.12 kg. During the last 8 days the average daily excretion was 0.63 gm., which is lower than the average daily excretion for the entire period. The dogs were then fasted for 5 days, but the daily administration of borneol was continued.