Controls the reversible conversion of biologically active glucocorticoids such as 11-dehydrocorticosterone to corticosterone in the presence of NADP(H) (PubMed:9405715, PubMed:23415904, PubMed:30902677). Participates in the corticosteroid receptor-mediated anti-inflammatory response, as well as metabolic and homeostatic processes (PubMed:9405715). Bidirectional in vitro, predominantly functions as a reductase in vivo, thereby increasing the concentration of active glucocorticoids (PubMed:23415904). It has broad substrate specificity, besides glucocorticoids, it accepts other steroid and sterol substrates (PubMed:23415904). Interconverts 7-oxo- and 7-hydroxy-neurosteroids such as 7-oxopregnenolone and 7beta-hydroxypregnenolone, 7-oxodehydroepiandrosterone (3beta-hydroxy-5-androstene-7,17-dione) and 7beta-hydroxydehydroepiandrosterone (3beta,7beta-dihydroxyandrost-5-en-17-one), among others (By similarity). Catalyzes the stereo-specific conversion of the major dietary oxysterol, 7-ketocholesterol (7-oxocholesterol), into the more polar 7-beta-hydroxycholesterol metabolite (PubMed:23415904). 7-oxocholesterol is one of the most important oxysterols, it participates in several events such as induction of apoptosis, accumulation in atherosclerotic lesions, lipid peroxidation, and induction of foam cell formation (By similarity). Mediates the 7-oxo reduction of 7-oxolithocholate mainly to chenodeoxycholate, and to a lesser extent to ursodeoxycholate, both in its free form and when conjugated to glycine or taurine, providing a link between glucocorticoid activation and bile acid metabolism (By similarity). Catalyzes the synthesis of 7-beta-25-dihydroxycholesterol from 7-oxo-25-hydroxycholesterol in vitro, which acts as ligand for the G-protein-coupled receptor (GPCR) Epstein-Barr virus-induced gene 2 (EBI2) and may thereby regulate immune cell migration (PubMed:30902677). an 11beta-hydroxysteroid + NADP(+) = an 11-oxosteroid + H(+) + NADPH corticosterone + NADP(+) = 11-dehydrocorticosterone + H(+) + NADPH a 7beta-hydroxysteroid + NADP(+) = a 7-oxosteroid + H(+) + NADPH 7-oxocholesterol + H(+) + NADPH = 7beta-hydroxycholesterol + NADP(+) chenodeoxycholate + NADP(+) = 7-oxolithocholate + H(+) + NADPH 7-oxolithocholate + H(+) + NADPH = NADP(+) + ursodeoxycholate glycochenodeoxycholate + NADP(+) = 7-oxoglycolithocholate + H(+) + NADPH NADP(+) + taurochenodeoxycholate = 7-oxotaurolithocholate + H(+) + NADPH NADP(+) + tauroursodeoxycholate = 7-oxotaurolithocholate + H(+) + NADPH glycoursodeoxycholate + NADP(+) = 7-oxoglycolithocholate + H(+) + NADPH 7-oxopregnenolone + H(+) + NADPH = 7beta-hydroxypregnenolone + NADP(+) 3beta,7alpha-dihydroxyandrost-5-en-17-one + NADP(+) = 3beta-hydroxy-5-androstene-7,17-dione + H(+) + NADPH 3beta-hydroxy-5-androstene-7,17-dione + H(+) + NADPH = 3beta,7beta-dihydroxyandrost-5-en-17-one + NADP(+) 3beta-hydroxy-5alpha-androstane-7,17-dione + H(+) + NADPH = 3beta,7beta-dihydroxy-5alpha-androstan-17-one + NADP(+) Steroid metabolism. Homodimer. Widely expressed. Highest levels (mRNA) in liver, kidney and lung, lower levels in the cerebellum, cortex, hippocampus, ovary, testis and thymus, no expression in colon. In null mice, 11-keto corticosteroids cannot be reduced to active 11-hydroxy forms (PubMed:9405715). Plasma corticosterone levels actually are elevated at the diurnal nadir (PubMed:9405715). Males display adrenocortical hyperplasia (PubMed:9405715). During starvation, induction of hepatic glucose-6-phosphatase (G6Pase) mRNA and enzyme activity is lost and the induction of phosphoenolpyruvate carboxykinase (PEPCK) is attenuated (PubMed:9405715). Liver glycogen levels significantly increase in the fed state (PubMed:9405715). The liver shows a phenotype of partial glucocorticoid deficiency, despite somewhat increased basal plasma corticosterone levels (PubMed:9405715). Belongs to the short-chain dehydrogenases/reductases (SDR) family.