Purification and properties of a sheep liver 21-hydroxysteroid nictoinamide adenine dinucleotide oxidoreductase.

The chemical syntheses of the 21-dehydro derivatives’ of a number of C1r a-ketolsteroids, including cortisone (3),2 cortisol (3), deoxycorticosterone (4), and Al-cortisone (5), have been described. The biological activities of the 11-oxygenated 21dehydrocorticosteroids were found to be similar to the corresponding 2l-hydroxysteroids. Schneider (6) reported that aqueous extracts of rat liver acetone powder reduced 21-dehydrocortisone to cortisone and suggested that the biological response to this derivative may be due to its reduction to cortisone. Since the physiological effects of other 21-dehydrosteroids may depend on their prior reduction to the corresponding alcohols, we have initiated investigations of the metabolism of 21-dehydrocorticosteroids. A previous note from this laboratory (7) reported the reduction of 21-dehydrocortisol by rat tissues. This paper describes the purification and some properties of an enzyme from sheep liver that catalyzes the reversible reduction of 21-dehydrosteroids.