Reaction catalyzed by 3(or 17)beta-hydroxysteroid dehydrogenase (1.1.1.51), testosterone 17beta-dehydrogenase (NADP+) (1.1.1.64)
+
NADPH
=
+
NADP+
androstanedione
+
NADPH
=
dihydrotestosterone
+
NADP+