Kinetic study of the enzymatic inactivation of progestogens by rat liver microsomes

The kinetics of enzymatic hydrogenation of synthetic progestogens by female rat liver microsomes with NADPH as hydrogen donor were investigated by means of an optical test. Steroids with high progestational activity (Clauberg test) showed a low hydrogenation rate (Vmax). There also seemed to be a certain correlation between molecular structure and Vmax. The metabolites from incubation with the progestogens were isolated from the micro-preparations, and identified by infrared spectroscopy. It was found that the hydrogenation of the olefinic and carbonylic groups involved the uptake of hydrogen from NADPH.