Reaction catalyzed by 3alpha(17beta)-hydroxysteroid dehydrogenase (NAD+) (1.1.1.239)

		+		NAD+	=			+		NADH
	5beta-pregnan-3alpha,21-diol-20-one	+		NAD+	=		5beta-pregnan-21-ol-3,20-dione	+		NADH