Literaturdatenbank
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Desvages, G., & Pieau, C. (1991). Steroid metabolism in gonads of turtle embryos as a function of the incubation temperature of eggs. The Journal of Steroid Biochemistry and Molecular Biology, 39(2), 203–213.
Added by: Admin (27 Jun 2009 12:36:19 UTC) |
| Resource type: Journal Article BibTeX citation key: Desvages1991 View all bibliographic details  |
Categories: General Keywords: Emydidae, Emys, Emys orbicularis, Schildkröten = turtles + tortoises, Zeitigung = incubation Creators: Desvages, Pieau Collection: The Journal of Steroid Biochemistry and Molecular Biology |
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| Abstract |
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In embryos of many reptiles, the sexual differentiation of gonads is temperature-dependent. In the turtle Emys orbicularis, all individuals become phenotypic males at 25°C, whereas 100% phenotypic females are obtained at 30°C. Steroid metabolism in embryonic gonads was studied at both temperatures, during and after the thermosensitive period for sexual differentiation. Pools of gonads were incubated for various times, with 3β-hydroxy-5-pregnen-20-one (pregnolone), progesterone, dehyddroepiandrosterone or 4-androsterone-3, 17-dione as substrates. The analysis of metabolites combined two successive chromatographies (HPLC and TLC) and autoradiography. Conversion of pregnenolen to progesterone and of dehydroepiandrosterone to 4-androstene-3,17-dione was more important in testes at 25°C than in ovaries at 30°C. In ovaries, a large amount of 5-pregnene-3β-diol was formed from pregnenolone, and 5-androstene-3β,17β-diol was produced from dehydroepiandrosterone. In both testes and ovaries, 5α-pregnane and 5α-androstane derivatives were the main metabolites obtained from progesterone and 4-androstene-3,17-dione, respectively. Progesterone was also converted to 20β-hydroxy-4-pregnen-3-one. Dehydroepiandrosterone and 4-androstene-3,17-dione were also metabolized into 11β-hydroxy-4-androstene-3,17-dione (only in testes), testosterone, 11β, 17β-dihydroxy-4-androstene-3-one, 17β-hydroxy-4-androstene-3,11-dione (low amounts in testes, traces in ovaries), 17α-hydroxy-4-androstene-3-one, estrone and estradiol-17β (traces).
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