NADPH-dependent oxidoreductase which catalyzes the reduction of a variety of compounds bearing carbonyl groups including ketosteroids, alpha-dicarbonyl compounds, aldehydes, aromatic ketones and quinones. Reduces 3-ketosteroids and benzil into 3beta-hydroxysteroids and R-benzoin, respectively, in contrast to the stereoselectivity of non-primate DHRS4s which produce 3alpha-hydroxysteroids and S-benzoin. Diplays low activity toward all-trans-retinal and no activity toward 9-cis-retinal as compared to non-primate mammals. In the reverse reaction, catalyze the NAD-dependent oxidation of 3beta-hydroxysteroids and alcohol, but with much lower efficiency. Involved in the metabolism of 3beta-hydroxysteroids, isatin and xenobiotic carbonyl compounds.; [Isoform 7]: No detected catalytic activity in vitro, possibly due to the lack of catalytic site.; [Isoform 8]: NADPH-dependent oxidoreductase which catalyzes the reduction of a variety of compounds bearing carbonyl groups including ketosteroids, alpha-dicarbonyl compounds, aldehydes, aromatic ketones and quinones. Involved in the metabolism of 3beta-hydroxysteroids, isatin and xenobiotic carbonyl compounds. Has a higher catalytic activity for xenobiotic alpha-dicarbonyl compounds, sucha as benzil, than isoform 1 and is involved in benzil detoxification.