Elevated expression of P450c17 (CYP17) during testicular formation in the frog

Ryosuke Iwade, Koichi Maruo, Goro Okada, Masahisa Nakamura*

*Corresponding author for this work

    Research output: Contribution to journalArticlepeer-review

    47 Citations (Scopus)


    Sex steroids play decisive roles in gonadal differentiation in many species of vertebrates. The sex can be changed by sex steroids in some species of amphibians, but the mechanism of the sex-reversal is largely unknown. In this study, we cloned and characterized 3 cDNAs encoding sex steroid-synthesizing enzymes, i.e., CYP11A1, CYP17 and 3β-HSD from the frog Rana rugosa. RT-PCR analysis showed that the CYP17 expression was much higher in male gonads than in female ones during sex determination in R. rugosa, whereas CYP11A1 and 3β-HSD showed no sexually dimorphic expression. When testosterone was injected into tadpoles for female-to-male sex reversal, CYP17 expression appeared to be very strong in the gonad at days 16 and 24 after injection of testosterone. CYP11A1 was also transcribed higher at day 16, but its expression was weaker when compared with that of CYP17. The expression of 3β-HSD did not change during the sex reversal. In addition, in situ hybridization analysis revealed that CYP17 was expressed in somatic cells of the indifferent male gonad and in those of the testis. Positive signals of CYP17 were also produced in somatic cells of a female-to-male sex-reversed gonad (testis) at days 16 and 24 post testosterone injection, but not in the ovary. Taken together, the results suggest that CYP17 is very involved in testicular differentiation of the gonad in R. rugosa.

    Original languageEnglish
    Pages (from-to)79-87
    Number of pages9
    JournalGeneral and Comparative Endocrinology
    Issue number1
    Publication statusPublished - 2008 Jan 1


    • 3β-HSD
    • Amphibians
    • CYP11A1
    • CYP17
    • CYP19
    • In situ hybridization
    • Rana rugosa
    • RT-PCR
    • Sex reversal

    ASJC Scopus subject areas

    • Endocrinology


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