Retinol Dehydrogenase 9 (RDH9)

rdh9 expression in embryonic liver, ganglia, small intestine, lung, skin and vertebral cartilage. In adult, in situ hybridization revealed rdh9 expression intensely in hepatocytes, weakly in kidney glomerulus, and intensely in collecting tubules. In intestine, undifferentiated epithelia had greater expression than differentiated epithelia at the distal villus end. Testes expressed rdh9 in spermatogonia, and weakly in Leydig cells. Adult brain expressed rdh9 in the dentate gyrus and CA regions of the hippocampus, the cerebellum Purkinje cells, and the glomerular and mitral cell layers of the olfactory bulb. Rdh9-null mice, backcrossed against C57BL/6J mice, were born in Mendelian frequency, were healthy and fertile, and had normal tissue retinoid and serum dihydrotestosterone levels. Expression of rdh1, a gene that encodes an efficient retinol dehydrogenase, decreased 3- to 8-fold in rdh9-nu11 mice, depending on dietary vitamin A.