NADPH-dependent oxidoreductase which catalyzes the reduction of some steroids (estrone, androstene-3,17-dione and cortisone) as well as prostaglandin E1, isatin and xenobiotics in vitro. May have a role in steroid and/or xenobiotic metabolism. 17alpha-estradiol + NADP(+) = estrone + H(+) + NADPH NADP(+) + testosterone = androst-4-ene-3,17-dione + H(+) + NADPH H(+) + NADPH + prostaglandin E1 = NADP(+) + prostaglandin F1 H(+) + isatin + NADPH = 3-hydroxyindolin-2-one + NADP(+) May be attached to the ER membrane by its C-terminus segment. May be attached to the ER membrane by its C-terminus segment. Belongs to the short-chain dehydrogenases/reductases (SDR) family.