Andersson E, Fjelldal P G, Klenke U, Vikingstad E, Taranger G L, Zohar Y, Stefansson S O
Department of Fisheries and Marine Biology, University of Bergen, P.O. Box 7800, N-5020, Bergen, Norway.
Comp Biochem Physiol B Biochem Mol Biol. 2001 Jun;129(2-3):551-8. doi: 10.1016/s1096-4959(01)00363-3.
Three forms of GnRH, chicken (c) GnRH-II, salmon (s) and seabream (sb) GnRH, were immunologically characterized in the brain and pituitary of turbot by ELISA. cGnRH-II and sGnRH were detected in the brain, while sbGnRH and sGnRH (but not cGnRH-II) were detected in the pituitary. In females, the levels of cGnRH-II in the turbot brain extracts increased from May to July, concomitant with an increase in oocyte diameter. In the pituitary, sbGnRH was found to be the dominant form, with levels 100-600-fold those of sGnRH. Both sGnRH and sbGnRH in the pituitary showed variation during the spawning season; sbGnRH increased from May to July and correlated with the increase in oocyte diameter, while sGnRH decreased. The overall patterns were the same for male turbot, although levels were generally lower. These findings suggest that sbGnRH could be controlling reproduction in the turbot. However, the seasonal variation in sGnRH indicates a potential physiological role in turbot reproduction. This study gives the first immunological indications that sbGnRH is present in the pituitary of a pleuronectiform fish, and will provide the basis for further studies on the endocrine regulation of reproduction in flatfish.
通过酶联免疫吸附测定法（ELISA）对三种促性腺激素释放激素（GnRH）形式，即鸡（c）GnRH-II、鲑鱼（s）GnRH和海鲷（sb）GnRH，在大菱鲆的脑和垂体中的免疫特性进行了研究。在脑中检测到了cGnRH-II和sGnRH，而在垂体中检测到了sbGnRH和sGnRH（但未检测到cGnRH-II）。在雌性大菱鲆中，5月至7月期间，其脑提取物中cGnRH-II的水平升高，同时伴随着卵母细胞直径的增加。在垂体中，sbGnRH是主要形式，其水平是sGnRH的100 - 600倍。垂体中的sGnRH和sbGnRH在产卵季节均表现出变化；sbGnRH从5月至7月升高，且与卵母细胞直径的增加相关，而sGnRH则下降。雄性大菱鲆的总体模式相同，尽管水平通常较低。这些发现表明，sbGnRH可能控制着大菱鲆的繁殖。然而，sGnRH的季节性变化表明其在大菱鲆繁殖中具有潜在的生理作用。本研究首次提供了免疫学证据，表明sbGnRH存在于鲽形目鱼类的垂体中，并将为进一步研究比目鱼繁殖的内分泌调节提供基础。
