Comparison of the Absorption and Destruction of the Lactone and Salt Form of Glucuronic Acid by Dogs

¹ From the Department of Biochemistry, Northwestern University Medical School, Chicago, Illinois

Comparative studies were made on the fate of d-glucuronolactone and d-glucuronate in dogs. The studies included: a) measurement of the rate of conversion of the lactone into the salt form at various ph values ranging from 2.0 to 7.4; b) measure of the rate of absorption from isolated loops of small intestine; c) determination of the blood plasma concentration in relation to intestinal absorption of the two forms of glucuronic acid in normal, Eck fistula and nephrectomized animals; d) the stability and magnitude of the plasma values were determined following the intravenous injection of the lactone or salt form of glucuronic acid into nephrectomized dogs. From the foregoing studies, it was determined that: a) glucuronolactone is rapidly converted into glucuronate at the ph of plasma; b) glucuronolactone is absorbed from the small intestine much more rapidly than is glucuronate; c) absorbed glucuronolactone is metabolized rapidly while glucuronate appears to be relatively inert in the body and to occupy a space similar to that of inulin. The limiting factor in the metabolism of glucuronolactone is the rate of its conversion into the salt form.