Glucuronic acid labeled with

Studies on the fate of D-glucuronic acid labeled with C14 have been mentioned previously in this review (Section IV, 2b). It is evident from these reports that extensive degradation of the molecule takes place, revealed by the large amount of carbon dioxide recovered. It is also clear that fragments of the acid are available for the resynthesis of D-glucuronic acid, and hence, perhaps, of D-glucose as well. 

The metabolism of an oral dose of 50-100 mg/kg "C-1,3-DNB was followed in rabbits (Parke 1961). Of the metabolites detected in urine, 30% were conjugated with glucuronic acid and 6% with sulfate. The major urinary metabolites of 1,3-DNB were 2,4-diaminophenol (31%), 1,3-phenylenediamine (25%), 1,3-nitroaniline (18%), and 2-amino-4-nitrophenol (14%). Other minor metabolites comprising about 20% of the label were oxidation and reduction products and azoxy dimers. 

In these experiments, several doubly and triply labelled compounds were reported.108 So-called UDP-D-[U-I4C, 3,4- H]glucuronic acid was formed by mixing UDP-D-[U-14C]glucuronic acid, UDP-d-[3-3H]glucuronic acid, and UDP-D-[4-3H]glucuronic acid it was not, of course, a triply labelled compound, but a mixture of 3 singly labelled ones.108 This factor prevented any conclusions about intramolecular transfer with doubly or triply labelled compounds to be reached. 

Glucose, mandelamine, and hydrochlorothorazide decrease the amount of estriol found when acid hydrolysis is used to release estriol from its conjugate with glucuronic acid in urine. The destruction of estriol in diabetic urine can be monitored by the inclusion of internal standards of labeled estriol glucuronide and reduced by prior dilution of the urine. When glucuronidase is used to release the estriol, the results are not affected when glucose of diabetic urine is present. When this is done the internal standard is not necessary. 

Sowden82 recently has prepared D-glucuronic acid isotopically labeled at carbon atom 6 for certain chemical and biochemical studies. In this novel synthesis, 5-aldehydo-l,2-isopropylidene-D-xylofuranose88 (XVI), prepared by periodate cleavage of 1,2-isopropylidene-a-D-glucofuranose (XV), was condensed with Cu-labeled sodium cyanide. Alkaline... 

The ability of the rat to use lactate, pyruvate, and D-glucose to equal extents in the synthesis of 1-naphthyl D-glucosiduronic acid was demonstrated by Packham and Butler.158 The lactate and pyruvate were labeled with C14 at the carboxyl carbon lactate labeled at Cl and C2 was also used and the D-glucose was uniformly labeled. D-Glucuronate-C14 was utilized for D-glucuronic conjugation on oral administration, but was twenty times as effective after intraperitoneal injection. 

The brominated sugars are usually quite stable and can be useful for a variety of purposes [151]. Substitution of bromine with deuterium can be used for preparation of labeled carbohydrates, while substitution with hydrogen sometimes can be used for inverting the stereochemistry. Noteworthy is the conversion of D-glucuronic acid derivative 61 into the corre-... 

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