The metabolism of cholesterol 25-hydroperoxide by subcellular fractions of rat and calf liver and of rat kidney was examined. The sole metabolic transformation observed was the reduction of the 25-hydroperoxide to the corresponding 25-alcohol 5-cholestene-3β,25-diol. No evidence of enzymic rearrangement of the 25-hydroperoxide to vicinal diol products was adduced. Neither cholesterol 25-hydroperoxide nor 5-cholestene-3β,25-diol was converted by rat liver homogenates to bile acids. Attempts to demonstrate cholesterol 25-hydroperoxide as a putative intermediate in the biosynthesis of bile acids from cholesterol in rat liver homogenates and calf liver microsomes by trapping techniques were unsuccessful. It was concluded that cholesterol 25-hydroperoxide is not implicated in cholesterol metabolism in liver or kidney tissues.
"La reducción de ambos isómeros determina la síntesis de 7α-y 7β-hidroxicoles- terol, mientras que su deshidratación induce la aparición de la forma 7-ketocolesterol (Teng et al., 1973). Asimismo, éste último puede surgir tras la descomposición hacia sus respectivos alcoholes de los isómeros 7α-y 7β-hidroxicoles- terol y posterior deshidratación (Teng et al., 1973a 1973b; Smith 1987; Nielson et al., 1996). En consecuencia, estos tres compuestos derivados del anillo B han sido identificados como los oxisteroles mayoritarios en distintos tipos de carne y productos cárnicos (Zubillaga y Maerker 1991; Gil 2002; Cayuela 2003). "
[Show abstract][Hide abstract] ABSTRACT: In order to rationalize multiphasic dose-response data evincing mutagenicity towards Salmonella typhimurium TA1537 for sterol hydroperoxides 3 beta-hydroxy-5 alpha-cholest-6-ene-5-hydroperoxide and 3 beta-hydroxycholest-5-ene-7 alpha-hydroperoxide their metabolism by the bacterial test strain was investigated. The 5 alpha-hydroperoxide was isomerized to the 7 alpha-hydroperoxide and reduced to 5 alpha-cholest-6-ene-3 beta,5-diol; the 7 alpha-hydroperoxide was reduced to cholest-5-ene-3 beta,7 alpha-diol and transformed to 3 beta-hydroxycholest-5-en-7-one. The 3 beta,5 alpha-diol and 3 beta,7 alpha-diol were not interconverted nor was either transformed to the 7-ketone.
Journal of Steroid Biochemistry 03/1987; 26(2):259-64. DOI:10.1016/0022-4731(87)90080-X
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