摘要：性类固醇激素对性腺发育期间的鱼类促性腺激素(GTH)分泌有负反馈作用，而对性未成熟的鱼类GTH分泌有正反馈...性类固醇激素对性腺发育期间的鱼类促性腺激素(GTH)分泌有负反馈作用，而对性未成熟的鱼类GTH分泌有正反馈作用。本实验选取性腺发育中期的长臀鮠(Cranoglanis bouderius)进行研究，将实验用鱼分成4组(实验重复3次，每组共用6尾鱼，)：①持续性17β-雌二醇(17β-Estradiol，E2)处理；②E2在注入促性腺激素释放激素类似物(Analogue of gonadotropin—releasing hormone，GnRH-A)脉冲刺激的处理；③持续性甲基睾酮(17α-methyltestosterone，MT)处理；④MT在注入GnRH-A脉冲刺激的处理；采用离体灌流孵育和GTH放射免疫测定的方法研究E2和MT对长臀鮠脑垂体GTH分泌的影响。持续性的E2(1μmol／L)处理能显著性地抑制长臀鮠脑垂体碎片基础GTH的分泌，而持续性的MT(1μmmol／L)处理能抑制长臀鮠脑垂体碎片基础GTH的分泌，同时E2和MT处理能抑制GnRH-A刺激的GTH分泌，而高浓度的E2和MT处理(10μmol／L)要比低浓度的E2和MT处理(0．1μmol／L)对长臀鮠脑垂体碎片基础GTH释放抑制能力强。这些结果表明，在离体实验中，E2和MT对性腺发育中期的长臀鮠脑垂体的GTH的分泌具有负反馈的作用，并且可能直接参与了长臀鮠脑垂体的GTH调节。显示全部
摘要：Changes in the pituitary and serum gonadotropin levels of Cranoglanis bouderius were studied at dif...Changes in the pituitary and serum gonadotropin levels of Cranoglanis bouderius were studied at different stages of ovarian development.Based on African catfish gonadotropin(cfGTH) and its anti-serum(Racf),heterologous radio-immunoassay(RIA) for the gonadotropin(GTH) of Cranoglanis bouderius was developed.The pituitary GTH contents at the late development stage were significantly higher than that at the mature,ovulation or regressed stages,while serum GTH levels at maturation and ovulation were significantly higher than that at late development and regressed stages,Injection of gonadotropin-releasing hormone analogue(GnRH-A) stimulated GTH secretion.Domperidone (DOM) had no effect on the basal serum GTH level.Injection of GnRH-A and DOM significantly enhanced the GTH levels stimulated by GnRH-A alone.These results indicate that GTH release in Cranoglanis bouderius is under the dual regulation of gonadotropin releasing hormone(GnRH) and dopamine(DA) from the hypothalamus,but DA can only inhibit GTH release induced by GnRH and not basal GTH release[Acta Zoologica Sinica 49(3):399-403.2003].显示全部
