17,20尾,21-Trihydroxy-4-pregnen-3-one biosynthesis and 20尾-hydroxysteroid dehydrogenase expression during final oocyte maturation in the protandrous yellowfin porgy, Acanthopagrus latus

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• 作者：Shan-Ru Jeng^a ; Wen-Shiun Yueh^a ; ^{yws@mail.nkmu.edu.tw} ; Yan-Horn Lee^b ; Hsiu-Fang Yen^a ; Ching-Fong Chang^c ; ^d ; ^{b0044@mail.ntou.edu.tw}
• 关键词：20尾-S ; 20尾-hsd ; Maturation-inducing steroid ; Yellowfin porgy
• 刊名：General and Comparative Endocrinology
• 出版年：2012
• 期刊代码：169_00166480
• 类别：bio
• 出版时间：1 April, 2012
• 卷：176
• 期：2
• 页码：192-200
• 文件大小：971 K

摘要

The purpose of this study was to investigate the physiological maturation-inducing steroid (MIS) in the marine protandrous yellowfin porgy (Acanthopagrus latus). Female fish were injected with 2 doses of LHRH analog (10 and 40 渭g per kg). Ovarian tissue was obtained at 6 h intervals for in vitro analysis of oocyte maturation. The most effective steroids for inducing in vitro maturation (germinal vesicle breakdown and GVBD) in cultured oocytes were 17,20尾-dihydroxy-4-pregnen-3-one (17,20尾P) and 17,20尾,21-trihydroxy-4-pregnen-3-one (20尾-S). 17,20尾P was less potent than 20尾S in inducing oocyte maturation. At higher concentrations, 11-deoxycortisol, 17伪-hydroxy-progesterone, and 20尾-21-dihydroxy-4-pregnen-3-one also significantly induced oocyte maturation. A tritiated precursor [³H]-pregnenolone, was cultured in vitro together with the maturing ovarian tissue. The tritiated metabolites were purified and identified by solvent extraction, HPLC, TLC, acetylation reaction and recrystallization. HPLC, TLC and recrystallization analysis showed that significant levels of tritiated 11-deoxycortisol (a precursor of 20尾-S) and 20尾-S, but not 17,20尾P, were biosynthesized from [³H]-pregnenolone. Similar TLC profiles were obtained from the tritiated products that were isolated from the HPLC/TLC 20尾-S fraction and standard 20尾-S after the acetylation reaction. Constant specific radioactivity of tritiated 11-deoxycortisol and 20尾-S but not 17,20尾P by recrystallization was obtained in the tritiated metabolites isolated from HPLC and TLC fractions. The expression of 20尾-hydroxysteroid dehydrogenase (20尾鈭扝SD) mRNA (a key enzyme that converts 11-deoxycortisol to 20尾-S) was significantly increased in maturing ovarian tissue. This study provides the first evidence that 20尾-S is converted from 11-deoxycortisol and is the possible MIS in yellowfin porgy.