| Literature DB >> 3138501 |
Abstract
The sulphotransferase and the glucuronyltransferase activities were measured with [3H]ethinyloestradiol in vitro using subcellular fractions from human liver. A rapid and sensitive assay based on a single extraction in ether of the unmetabolized EE2 is described. The mean (+/- SD) of the sulphotransferase and glucuronyltransferase activities from 8 livers was 68.2 +/- 16.5 and +/- 190.4 +/- 82.3 pmol/min/mg, respectively. The kinetic parameters of both enzymes were measured in 4 livers by varying the concentrations of EE2 or the endogenous substrate. At varying concentrations of EE2 the average (+/- SD) of Vmax was 66.5 +/- 15.8 pmol/min/mg (sulphotransferase) and 404 +/- 317 pmol/min/mg (glucuronyltransferase). The mean (+/- SD) of Km was 0.0072 +/- 0.0019 mM (sulphotransferase) and 0.20 +/- 0.12 mM (glucuronyltransferase).Entities:
Keywords: Biology; Contraception; Contraceptive Agents, Estrogen--analysis; Contraceptive Agents, Female--analysis; Contraceptive Agents--analysis; Developed Countries; Enzymes; Enzymes And Enzyme Inhibitors; Ethinyl Estradiol--analysis; Europe; Examinations And Diagnoses; Family Planning; Hepatic Effects; Histology; Laboratory Examinations And Diagnoses; Northern Europe; Physiology; United Kingdom
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Year: 1988 PMID： 3138501 DOI： 10.1016/0022-4731(88)90360-3
Source DB: PubMed Journal: J Steroid Biochem ISSN： 0022-4731 Impact factor: 4.292