Oocyte maturation-inducing steroids in protandrous black porgy, Acanthopagrus schlegeli.
The study objectives aimed to investigate the maturation-inducing steroid (MIS) in marine protandrous black porgy, Acanthopagrus schlegeli. The characteristics of oocyte maturation were also described. Females were injected with two successive doses of LHRH analog (LHRH-A, 10 and 50 microg/kg of fish). The ovarian tissue was obtained at 6-h intervals for in vitro oocyte maturation. Both 17,20 beta-dihydroxy-4-pregnen-3-one (DHP) and 17,20 beta,21-trihydorxy-4-pregnen-3-one (20 beta-S) were the most effective steroids to induce in vitro maturation (e.g. germinal vesicle breakdown, GVBD) in oocytes cultured for either 24 h or 1 min. 20 beta-S had a better potency than DHP in inducing oocyte maturation. 17-hydroxyprogesterone, 11-deoxycortisol, and 20 beta-21-dihydroxy-4-pregnen-3-one also significantly induced oocyte maturation at high concentrations. The process of oocyte maturation (after the injection of LHRH analog) was founded to be divided into four stages: hormone-insensitive stage (insensitive to gonadotropin and MIS); MIS-insensitive (respond to gonadotropin, but not MIS); MIS-sensitive (respond to MIS); and spontaneous stage (GVBD in the hormone-free condition), respectively. Cycloheximide blocked GVBD at the MIS-insensitive stage, control (hormone-free), and hormone-induced GVBD at the MIS-sensitive stage in a dose-dependent effect.
Yueh
Wen Shiun
WS
Department of Aquaculture, National Institute of Kaohsiung Marine Technology, Kaohsiung 811, Taiwan, ROC.
Chang
Ching Fong
CF
D000818:Animals; D002478:Cells, Cultured; D003513:Cycloheximide / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D005260:Female; D066298:In Vitro Techniques; D009865:Oocytes / Q000166:cytology / Q000187:drug effects*; D009866:Oogenesis / Q000187:drug effects*; D010473:Perciformes; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D013256:Steroids / Q000494:pharmacology*; D013997:Time Factors
D011500:Protein Synthesis Inhibitors; D013256:Steroids; D003513:Cycloheximide