Reaction catalyzed by 3beta-hydroxysteroid 3-dehydrogenase (1.1.1.270)
+
NADPH
+
=
+
NADP+
5beta-pregnane-21-ol-3,20-dione
+
NADPH
+
H+
=
5beta-pregnane-3beta,21-diol-20-one
+
NADP+
