May function in the pulmonary metabolism of endogenous carbonyl compounds, such as aliphatic aldehydes and ketones derived from lipid peroxidation, 3-ketosteroids and fatty aldehydes, as well as in xenobiotic metabolism. a secondary alcohol + NADP(+) = a ketone + H(+) + NADPH Allosteric enzyme exhibiting negative cooperativity. Activated 2-5 fold by fatty acids. Homotetramer. Lung (ciliated cells, non-ciliated bronchiolar cells and type-II alveolar pneumocytes). Low expression in all extrapulmonary tissues, including adipose tissue. By glucocorticoids. Uses both NADP and NAD as substrates. Has a strong preference for NADP. Belongs to the short-chain dehydrogenases/reductases (SDR) family.