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Fachbereich Veterinärmedizin



    Steroidogenesis during in vitro maturation of bovine cumulus oocyte complexes and possible effects of tri-butyltin on granulosa cells (2000)

    Schönfelder, M.
    Schams, D.
    Einspanier, R.
    15th International Symposium of the Journal of Steroid Biochemistry and Molecular Biology ""Recent Advances in Steroid Biochemistry and Molecular Biology""Recent Advances in Steroid Biochemistry and Molecular Biology
    München, 17. – 20.05.2000
    The journal of steroid biochemistry and molecular biology
    Seiten: 291 – 300
    ISSN: 0960-0760
    Institut für Veterinär-Biochemie

    Oertzenweg 19 b
    14163 Berlin
    +49 30 838 62225

    Abstract / Zusammenfassung

    Steroids are known as important factors on the route of oocytes development and cumulus oocyte complexes (COC) as well as follicular granulosa cells (GC) are suggested to be themselves involved in steroidogenesis. The aim of this study was to characterize such a local sex steroidogenic system during in vitro maturation (IVM) of bovine COCs according to the production of estradiol (E), testosterone (T) and progesterone (P). The expression of two steroid-converting key-enzymes was measured in parallel by quantitative RT-PCR. Furthermore, possible effects of the environmental pollutant tri-butyltin (TBT) were elucidated for the first time on bovine COC and GC in vitro concerning that steroidogenic system.

    During IVM of bovine COCs concentrations of P increased continuously, corresponding with steady-state levels of 3-beta-hydroxy-steroid-dehydrogenase (HSD) transcripts. In contrast, E together with P450 aromatase mRNA (ARO) increased in the first hours of IVM but declining thereafter, whereas T reached almost balanced levels. However, TBT showed only slight effects during IVM of COC. In cultured GC, LH caused highest P- and E-production within 24 h and treatment with 50 pM TBT induced a significant decrease of E in contrast to 100 pM TBT and the control. These results indicate, that (1) COCs were able to modulate their steroidogenic environment in vitro and that (2) TBT may possibly influence or disturb steroidogenesis in the cows reproductive tract shown here for GC