title: Immunohistochemical detection and biological activities of CYP17 (P450c17) in the indifferent gonad of the frog Rana rugosa.
abstract: Sex steroids play a crucial role in the gonad differentiation in various species of vertebrates. However, little is known regarding the localization and biological activity of steroid-metabolizing enzymes during gonadal sex differentiation in amphibians. In the present study, we showed by real-time RT-PCR analysis that the expression of CYP17, one of the key steroidogenic enzymes, was higher in the indifferent gonad during sex differentiation in male than in female tadpoles of Rana rugosa but that there was no difference detected in the 3betaHSD mRNA level between the male and female gonads. We next examined the localization of CYP17, 3betaHSD and 17betaHSD in the indifferent and differentiating gonads by using three kinds of antibodies specific for CYP17, 3betaHSD and 17betaHSD, respectively. Positive signals for CYP17, 3betaHSD and 17betaHSD were observed in somatic cells of the indifferent gonad of males and in the interstitial cell of the testis. The enzymatic activity of CYP17 was also examined in the gonad during sex differentiation in this species. [(3)H]Progesterone (Prog) was converted to [(3)H]androstenedione (AE) in the indifferent gonad in males and females, but the rate of its conversion was higher in males than in females. Moreover, fluorescence in situ hybridization (FISH) analysis revealed that the CYP17 gene was located on the q arm of chromosome 9, indicating that CYP17 was autosomal in R. rugosa. Taken together, the results demonstrate that the CYP17 protein is synthesized in somatic cells of the indifferent gonad during gonadal sex differentiation in R. rugosa and that it is more active in converting Prog to AE in males than in females. The data suggest that CYP17 may be involved in testicular formation during sex differentiation in this species.
authors.affiliation: Department of Biology, Faculty of Education and Integrated Arts and Sciences, Waseda University, Shinjuku-ku, Tokyo, Japan.
authors.forename: Nana
authors.initials: N
authors.lastname: Sakurai
authors.forename: Koichi
authors.initials: K
authors.lastname: Maruo
authors.forename: Shogo
authors.initials: S
authors.lastname: Haraguchi
authors.forename: Yoshinobu
authors.initials: Y
authors.lastname: Uno
authors.forename: Yuki
authors.initials: Y
authors.lastname: Oshima
authors.forename: Kazuyoshi
authors.initials: K
authors.lastname: Tsutsui
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Matsuda
authors.forename: Jean-Luc
authors.initials: JL
authors.lastname: Do Rego
authors.forename: Georges
authors.initials: G
authors.lastname: Pelletier
authors.forename: Hubert
authors.initials: H
authors.lastname: Vaudry
authors.forename: Masahisa
authors.initials: M
authors.lastname: Nakamura
mesh_terms: D015067:17-Hydroxysteroid Dehydrogenases / Q000378:metabolism; D015096:3-Hydroxysteroid Dehydrogenases / Q000378:metabolism; D000735:Androstenedione / Q000378:metabolism; D000818:Animals; D002454:Cell Differentiation; D005260:Female; D006066:Gonads / Q000196:embryology / Q000201:enzymology* / Q000254:growth & development; D008297:Male; D011374:Progesterone / Q000378:metabolism; D011898:Ranidae / Q000196:embryology / Q000254:growth & development / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012733:Sex Differentiation; D013254:Steroid 17-alpha-Hydroxylase / Q000378:metabolism*; D013737:Testis / Q000196:embryology / Q000201:enzymology / Q000254:growth & development
chemical_list: D000735:Androstenedione; D011374:Progesterone; D015067:17-Hydroxysteroid Dehydrogenases; D015096:3-Hydroxysteroid Dehydrogenases; D013254:Steroid 17-alpha-Hydroxylase