Reaction catalyzed by 3-oxo-5alpha-steroid 4-dehydrogenase (NADP+) (1.3.1.22)

		+		NADPH	=			+		NADP+
	17alpha-hydroxyprogesterone	+		NADPH	=		17alpha-hydroxy-5alpha-pregnan-3,20-dione	+		NADP+