Glucuronide synthesis in kidney and gastrointestinal tract

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Abstract
Synthesis of the glucuronides of o-aminophenol, o-aminobenzoic acid and (-) -menthol is reported in slice and homogenate preparations of kidney cortex and gastrointestinal mucosa from several animals. In broken-cell systems, synthesis was affected by enzymic transfer of glucuronic acid from uridine diphosphate glucuronic acid to the acceptor sub-strate, the uridine diphosphate transglucuronylase responsible being associated with the microsomal fraction. It would appear that this is a major pathway of glucuronide formation in such tissues, and evidence of others could not be obtained. Uridine diphosphate glucuronic acid has been shown to be present in kidney and gastric tissue, and to be formed there by the DPN-dependent oxidation of uridine diphosphate glucose. Synthesis of o-aminophenyl glucuronide is lower in preparations of kidney and gastrointestinal mucosa than in those of liver; reasons for this are discussed and the parts played by conjugate and nucleotide hydrolysis evaluated. Development of o-aminophenyl glucuronide synthesis and of observable uridine diphosphatetransglu-curonylase activity in fetal and infant guinea-pig kidney and stomach is followed and its significance discussed. Experiments with bili-rubin are reported. Various factors affecting glucuronide synthesis and observed uridine diphosphate-transglucuronylase activity are described and the care required in interpreting quantitative work with the unpurified enzyme is emphasized.