Has dehydrogenase activity against corticosterone (11 beta-hydroxysteroid) and estradiol (17 beta-hydroxysteroid), with similar activities to both sterols in the presence of NADP(+), but negligible activity to either sterol in the presence of NAD(+). May be involved in signal transduction regulated by various sterols. an 11beta-hydroxysteroid + NADP(+) = an 11-oxosteroid + H(+) + NADPH corticosterone + NADP(+) = 11-dehydrocorticosterone + H(+) + NADPH 17beta-estradiol + NADP(+) = estrone + H(+) + NADPH Surface of oil bodies. Exists at a monolayer lipid/water interface. Expressed in seeds (at protein level) (PubMed:15331088, PubMed:9816677). Not expressed in stem, leaf or root (at protein level) (PubMed:9816677). Expressed during seed maturation (PubMed:15331088, PubMed:9816677). Appears in maturing seeds approximately 3 weeks after flowering and thereafter the level is maintained at a steady level till the late stage of seed maturation (at protein level). Detected in maturing seeds 2-3 weeks after flowering, progressively increasing to the maximal level in the following 2 weeks, and diminishing thereafter to a relatively low level at the late stage of seed maturation (PubMed:15331088). The proline-knob motif may be involved in the targeting to oil bodies. Belongs to the short-chain dehydrogenases/reductases (SDR) family.