Side-chain oxidation of monooxygenated C27- and C29-steroids in rat liver mitochondria and 18000 x g supernatant.
The 24-, 25- and 26-hydroxylation of 4-cholesten-3 alpha-ol, 4-cholesten-3 beta-ol, 5-cholesten-3 alpha-ol, 5-cholesten-3 beta-ol, 5 alpha-cholestan-3 alpha-ol, 5 alpha-cholestan-3 beta-ol, 5 beta-cholestan-3 alpha-ol, 5 beta-cholestan-3 beta-ol, 4-cholesten-3-one, 5 alpha-cholestan-3-one, 5 beta-cholestan-3-one and the 24 alpha-ethyl derivatives of 5 alpha-cholestan-3 beta-ol, 5 beta-cholestan-3 alpha-ol, 5 beta-cholestan-3 beta-ol and 4-cholestan-3-one were studied in rat liver mitochondria (8500 x g sediment fractions fortified with isocitrate) and in rat liver microsomes (18000 x g supernatants supplemented with NADPH). In the mitochondria, all C27-substrates and probably all C29-substrates were found to be omega-hydroxylated. From 24 alpha-ethyl-5 alpha-cholestan-3 beta-ol and 24 alpha-ethyl-4-cholesten-3-one two omega-hydroxylated products were identified. All C27- but no C29-steroids were found to be 24- and 25-hydroxylated. The yield of omega-hydroxylated metabolites were much higher than those of the 24-, and 25-hydroxylated products. The omega-hydroxylation of the C29-steroids amounted to 3-50% of that found for the corresponding C27-steroids. In the 18000 x g supernatant only one substrate, 5 beta-cholestan-3 alpha-ol, was found to be 25- and 26-hydroxylated and no 24-hydroxylation of any steroid could be detected.
D000818:Animals; D002776:Cholestanes / Q000378:metabolism*; D002777:Cholestanols / Q000378:metabolism*; D002778:Cholestanones / Q000378:metabolism*; D002782:Cholestenes / Q000378:metabolism*; D002783:Cholestenones / Q000378:metabolism*; D002855:Chromatography, Thin Layer; D008401:Gas Chromatography-Mass Spectrometry; D006900:Hydroxylation; D008297:Male; D008862:Microsomes, Liver / Q000378:metabolism*; D008930:Mitochondria, Liver / Q000378:metabolism*; D051381:Rats
D002776:Cholestanes; D002777:Cholestanols; D002778:Cholestanones; D002782:Cholestenes; D002783:Cholestenones