In Vitro Reduction of 16α-Chloroestrone by Rat Liver

Abstract

As a series of the metabolic studies on the steroidal lipid-shifting drugs biotransformation of 16α-chloroestrone with the rat liver preparations has been investigated. The substrate was reduced to the 17β-hydroxyl derivative, when incubated with microsomes, but not with the 105000×g supernatant. In contrast, estrone was converted into estradiol with either of these enzyme preparations. The yield of 16α-chloroestradiol formed from 16α-chloroestrone by incubation with microsomes decreased with an increasing amount of added estrone indicating the occurrence of competitive inhibition. The properties of 17β-hydroxysteroid dehydrogenase involving 16α-chloroestrone have been described.