In vitro steroidogenesis by testicular fragments and ovarian follicles in a hybrid sturgeon, Bester |
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Authors: | B.M. Amiri M. Maebayashi S. Adachi G.P. Moberg S.I. Doroshov K. Yamauchi |
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Affiliation: | (1) Department of Biology, Faculty of Fisheries, Hokkaido University, Hakodate, 041, Japan;(2) Department of Research and Development, The Hokkaido Electric Power Co., Inc., Sapporo, 004, Japan;(3) Department of Animal Science, University of California Davis, Davis, CA 95616, USA |
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Abstract: | In this study, developmental changes in the steroidogenic capacity of testicular fragments and isolated ovarian follicles of a hybrid sturgeon, Bester, at a variety stage of developments were examined. Testicular fragments or isolated ovarian follicles were incubated in L-15 medium in the presence or absence of different concentrations of five preparations; forskolin, human chorionic gonadotropin (HCG), pregnenolone (P5), 17-hydroxyprogesterone (17OHP) and testosterone (T) for 18 h at 15 °C. After incubation, concentrations of 11-ketotestosterone (11 KT) (testis) and, 17-estradiol (E2) (ovarian follicles) and 17,20-dihydroxy-4-pregnen-3-one (DHP) (testis and ovarian follicles) were measured. 11KT was detected in the media following incubation with P5, 17OHP and T. Its concentration was higher during late spermatogenesis and prespermiation and lower at the degeneration stage. Both P5 and 17OHP were converted to DHP during the prespermiation stage. Forskolin had little stimulatory effect on the synthesis of 11KT and DHP and HCG did not induce the production of these steroids.E2 was detected in the medium following incubation of follicles with P5, 17OHP and T at all stages of oocyte development. The concentration of E2 in the medium increased during vitellogenesis with the peak production occurring at the tertiary yolk stage. In contrast, the potencies of follicles to produce steroids shifted to the production of DHP during migratory nucleus stage. Forskolin and HCG had little effect on the synthesis of E2 and DHP. These results demonstrated that the failure of spontaneous spermiation or ovulation is not due to the insufficient synthesis of DHP, but may due to the lack of availability of precursors. |
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Keywords: | Bester hybrid sturgeon testis ovary steroidogenesis 11-ketotestosterone 17 /content/U32L203172162184/xxlarge946.gif" alt=" beta" align=" MIDDLE" BORDER=" 0" >-estradial 17 /content/U32L203172162184/xxlarge945.gif" alt=" agr" align=" BASELINE" BORDER=" 0" > 20 /content/U32L203172162184/xxlarge946.gif" alt=" beta" align=" MIDDLE" BORDER=" 0" >-dihydroxy-4-pregnen-3-one |
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