• Development and Reproduction
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• v.12 no.1
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• pp.107-112
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• 2008

To investigate the $C_{21}$-steroids produced from maturating oocytes in the longchin goby, Chasmichthys dolichognathus, the oocytes ($0.74{\sim}0.97\;mm$) were incubated with radiolabeled $17{\alpha}$-hydroxyprogesterone ($^3H-17{\alpha}OHP$) for 24 hours. The resulting metabolites were analyzed by thin layer chromatography and identified by gas chromatography-mass spectrometry. Two $C_{21}$-steroids, $17{\alpha}$-hydroxy, $20{\alpha}$-dihydroprogesterone ($17{\alpha}20{\alpha}P$) and $17{\alpha}$-hydroxy, $20{\beta}$-dihydroprogesterone ($17{\alpha}20{\beta}P$), were converted from $^3H-17{\alpha}OHP$ in the maturing oocytes. These two main metabolites were detected at 0.80 mm diameter oocytes or greater. In addition, the effects of these metabolites on in vitro germinal vesicle breakdown (GVBD) were tested. The sensitivity of oocytes to the induction of GVBD was greater at $17{\alpha}20{\beta}P$ than $17{\alpha}20{\alpha}P$. This result showed that $17{\alpha}20{\beta}P$ is a major maturation inducing steroid (MIS) in longchin goby, suggesting $17{\alpha}20{\alpha}P$ may play a role in regulating the oocyte maturation process.

• Journal of Aquaculture
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• v.11 no.1
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• pp.119-124
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• 1998

The relative effectiveness of C21-steroids and human chorionic gonadotropin(HCG) on maturation and ovulatin was investigated in vitro using the isolated oocytes or ovarian fragments from the sea bass, Lateolabrax japonicus. ${\alpha}$-hydroxy, 20${\beta}$-dihydroprogesterone(17${\alpha}$20${\beta}$OHP : 5, 50, 500, 1000ng/ml), 17${\alpha}$-hydroxy, 20${\alpha}$-dihydroprogesterone(17${\alpha}$20${\alpha}$OHP : 5, 50, 500, 1000ng/ml) and HCG (5, 50, 500IU/ml) were effective in inducing oocyte maturation, GVM (germinal vesicle migration) or GVBD(germinal vesicle breakdown), compared to control except 17${\alpha}$20${\beta}$OHP and 17${\alpha}$20${\alpha}$OHP at 5ng/ml. 17${\alpha}$20${\beta}$OHP showed the greatest effect on oocyte maturation at 50ng/ml. A combination of 17${\alpha}$20${\beta}$OHP(50ng/ml) and HCG(500IU/ml) led to a significant increase (p<0.05) in GVBD when compared with 17${\alpha}$20${\beta}$OHP or HCG alone. These findings suggest that the two in combination acts synergistically to induce GVBD. 17${\alpha}$20${\beta}$OHP (1~1000ng/ml) and HCG(1~500IU/ml) also induced ovulation in ovarian fragments at all concentrations used ; more effective at lower concentrations(1~50ng/ml or IU/ml). It was shown that HCG was more potent in inducting ovulatin than 17${\alpha}$20${\beta}$OHP.