Studies of mammalian glucoside conjugation.
The mammalian glucoside-conjugation pathway was studied by using p-nitrophenol as the model substrate and mouse liver microsomal preparations as the source of enzyme. The microsomal preparations supplemented with UDP-glucose glucosylated p-nitrophenol; p-nitrophenyl glucoside was identified by chromatography in six solvent systems. The unsolubilized glucosyltransferase of fresh microsomal preparations did not follow the usual Michaelis-Menten kinetics and was easily inhibited by many steroids. All the steroids tested inhibited glucosylation of p-nitrophenol to a greater degree than glucuronidation of p-nitrophenol when assayed in the same microsomal preparations. The steroids inhibited glucosylation with the following decreasing effectiveness: pregnan-3alpha-ol-20beta-one (3alpha-hydroxypregnan-20-beta-one)>oestradiol-17beta 3-methyl ether>oestradiol-17beta>oestriol>pregnane-3alpha,20beta-diol>oestrone. Pregnan-3alpha-ol-20beta-one, pregnane-3alpha,20beta-diol and oestrone had negligible effect on glucuronidation.
D000818:Animals; D002247:Carbon Isotopes; D002854:Chromatography, Paper; D004967:Estrogens / Q000494:pharmacology; D005947:Glucose / Q000378:metabolism; D005964:Glucosyltransferases / Q000378:metabolism; D005965:Glucuronates / Q000096:biosynthesis* / Q000378:metabolism; D006027:Glycosides / Q000096:biosynthesis*; D006863:Hydrogen-Ion Concentration; D006914:Hydroxysteroids / Q000494:pharmacology; D007664:Ketosteroids / Q000494:pharmacology; D008099:Liver / Q000201:enzymology; D008297:Male; D051379:Mice; D008862:Microsomes, Liver / Q000187:drug effects / Q000378:metabolism; D009596:Nitrophenols; D011276:Pregnanediol / Q000494:pharmacology; D011278:Pregnanes / Q000494:pharmacology; D013347:Subcellular Fractions / Q000201:enzymology / Q000378:metabolism; D013997:Time Factors; D014461:Ultracentrifugation; D014539:Uridine Diphosphate Sugars / Q000378:metabolism
D002247:Carbon Isotopes; D004967:Estrogens; D005965:Glucuronates; D006027:Glycosides; D006914:Hydroxysteroids; D007664:Ketosteroids; D009596:Nitrophenols; D011278:Pregnanes; D014539:Uridine Diphosphate Sugars; D005964:Glucosyltransferases; D005947:Glucose; D011276:Pregnanediol