Reaction catalyzed by 11beta-hydroxysteroid dehydrogenase (NAD+) (1.1.1.B40)

		+		NAD+	=			+		NADH
	1beta,21-dihydroxypregn-4-en-3,20-dione	+		NAD+	=		21-hydroxy-pregn-4-en-3,11,20-trione	+		NADH