title: Species differences among various rodents in the conversion of 7alpha-hydroxycholesterol in liver microsomes.
abstract: Our previous study demonstrated that there are species differences among vertebrates in their conversion of 7alpha-hydroxycholesterol (7HC) to 7-ketocholesterol (7KC). To examine this further, we investigated the differences in the products of 7alpha-hydroxycholesterol in various species of male muroid rodents. Adult male Syrian hamsters (Mesocricetus auratus), dwarf hamsters (Phodopus rovolovskii), Djungarian hamsters (Phodopus sungorus), Chinese hamsters (Cricetulus griseus), rat-like hamsters (Tscherskia triton), and hispid cotton rats (Sigmodon hispidus) were used. Microsomal fractions were prepared from their livers, and the activities of the enzymes that participate in the dehydrogenation of 7alpha-hydroxycholesterol were determined by measuring the products using high-performance liquid chromatography. 7alpha-hydroxycholesterol was converted to both 7alpha-hydroxy-4-cholesten-3-one (7HCO) and 7-ketocholesterol in all of the hamsters tested. However, in the rat-like hamster and the hispid cotton rat, 7alpha-hydroxycholesterol was converted mostly to 7alpha-hydroxy-4-cholesten-3-one, as also observed in the rat (Rattus norvegicus). The results suggest that microsomal enzyme activity in the conversion of 7alpha-hydroxycholesterol to 7-ketocholesterol varies considerably, even within the subfamily Cricetinae and the family Muridae.
authors.affiliation: Department of Surgery I, Miyazaki University Hospital, Frontier Science Research Center, University of Miyazaki, Kiyotake, Japan. maedayo@post.miyazaki.med.ac.jp
authors.forename: Yorio
authors.initials: Y
authors.lastname: Maeda
authors.forename: Akio
authors.initials: A
authors.lastname: Shinohara
authors.forename: Chihiro
authors.initials: C
authors.lastname: Koshimoto
authors.forename: Kazuo
authors.initials: K
authors.lastname: Chijiiwa
mesh_terms: D000818:Animals; D002783:Cholestenones / Q000737:chemistry / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D006888:Hydroxycholesterols / Q000737:chemistry / Q000378:metabolism*; D007653:Ketocholesterols / Q000737:chemistry / Q000378:metabolism; D008297:Male; D008862:Microsomes, Liver / Q000737:chemistry / Q000378:metabolism*; D015394:Molecular Structure; D009115:Muridae / Q000378:metabolism*; D009929:Organ Size; D013045:Species Specificity; D013237:Stereoisomerism; D013997:Time Factors
chemical_list: D002783:Cholestenones; D006888:Hydroxycholesterols; D007653:Ketocholesterols; C002656:7 alpha-hydroxy-4-cholesten-3-one; C011724:cholest-5-en-3 beta,7 alpha-diol; C003001:7-ketocholesterol