title: Cellular localization of cytochrome P450IIA1 in testes of mature Sprague-Dawley rats.
abstract: Previous studies have shown that a prominent site of extrahepatic cytochrome P450IIA1 in male rats is the testis. We investigated the cellular location of cytochrome P450IIA1 in the testes of adult rats. Using specific isolation of testicular compartments and individual cell types, as well as in vivo removal of Leydig cells by ethane dimethyl sulfonate, we determined the cellular location of cytochrome P450IIA1 using testosterone hydroxylation assay, Western immunoblotting, and immunohistochemical analysis. Enriched Leydig cell fractions had the greatest testosterone 7 alpha-hydroxylase activity as well as immunoreactivity. Immunohistochemical analysis confirmed that the cellular location of cytochrome P450IIA1 was specific to Leydig cells. The specific localization of enzyme systems that are involved in xenobiotic activation may have important implications for inducing specific cell toxicity by compounds that exert their effects in the testes.
authors.affiliation: Department of Pharmacology & Toxicology, University of Arkansas for Medical Sciences, Little Rock 72205.
authors.forename: J E
authors.initials: JE
authors.lastname: Seng
authors.forename: J E
authors.initials: JE
authors.lastname: Leakey
authors.forename: M P
authors.initials: MP
authors.lastname: Arlotto
authors.forename: A
authors.initials: A
authors.lastname: Parkinson
authors.forename: J
authors.initials: J
authors.lastname: Gandy
mesh_terms: D000818:Animals; D001189:Aryl Hydrocarbon Hydroxylases; D015153:Blotting, Western; D003577:Cytochrome P-450 Enzyme System / Q000032:analysis*; D005260:Female; D006900:Hydroxylation; D007150:Immunohistochemistry; D007527:Isoenzymes / Q000032:analysis*; D007985:Leydig Cells / Q000201:enzymology; D008297:Male; D008861:Microsomes / Q000201:enzymology; D008862:Microsomes, Liver / Q000201:enzymology; D051381:Rats; D011919:Rats, Inbred Strains; D013250:Steroid Hydroxylases / Q000032:analysis* / Q000378:metabolism; D013737:Testis / Q000201:enzymology*; D013739:Testosterone / Q000378:metabolism
chemical_list: D007527:Isoenzymes; D013739:Testosterone; D003577:Cytochrome P-450 Enzyme System; D013250:Steroid Hydroxylases; D001189:Aryl Hydrocarbon Hydroxylases; C029009:steroid hormone 7-alpha-hydroxylase; C022724:testosterone 7-alpha-hydroxylase, hamster