Has NAD-dependent 17-beta-hydroxysteroid dehydrogenase activity. Converts oestradiol to oestrone. The physiological substrate is not known. Acts on oestradiol and 5-androstene-3-beta,17-beta-diol (in vitro). 17beta-estradiol + NAD(+) = estrone + H(+) + NADH androst-5-en-3beta,17beta-diol + NAD(+) = 3beta-hydroxyandrost-5-en-17-one + H(+) + NADH Homotetramer. Detected in retina. Belongs to the short-chain dehydrogenases/reductases (SDR) family.