Species differences among various rodents in the conversion of 7α-hydroxycholesterol in liver microsomes

• Published in: Steroids Vol. 71; no. 5; pp. 329 - 333
• Main Authors: Maeda, Yorio, Shinohara, Akio, Koshimoto, Chihiro, Chijiiwa, Kazuo
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Inc 01.05.2006; Elsevier Science
• Subjects: 7-Ketocholesterol; 7α-Hydroxycholesterol; Biological and medical sciences; Fundamental and applied biological sciences. Psychology; Hamster; Rodents; Vertebrates: endocrinology; 7-Ketocholesterol; 7α-Hydroxycholesterol; Rodents; Hamster; Vertebrata; Mammalia; Digestive system; Animal; Liver; Rodentia; Microsome
• ISSN: 0039-128X; 1878-5867
• DOI: 10.1016/j.steroids.2005.07.010

Our previous study demonstrated that there are species differences among vertebrates in their conversion of 7α-hydroxycholesterol (7HC) to 7-ketocholesterol (7KC). To examine this further, we investigated the differences in the products of 7α-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 7α-hydroxycholesterol were determined by measuring the products using high-performance liquid chromatography. 7α-hydroxycholesterol was converted to both 7α-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, 7α-hydroxycholesterol was converted mostly to 7α-hydroxy-4-cholesten-3-one, as also observed in the rat ( Rattus norvegicus). The results suggest that microsomal enzyme activity in the conversion of 7α-hydroxycholesterol to 7-ketocholesterol varies considerably, even within the subfamily Cricetinae and the family Muridae.