Unal G, Erdoğan E, Oğuz A R, Kaptaner B, Kankaya E, Elp M
Department of Biology, Faculty of Science and Literature, Yüzüncü Yil University, Van, Turkey.
Fish Physiol Biochem. 2008 Dec;34(4):447-54. doi: 10.1007/s10695-008-9203-8. Epub 2008 Mar 8.
Chalcalburnus tarichi is an endemic cyprinid species living in the Lake Van basin, in eastern Anatolia, Turkey. The present study was undertaken to determine which hormones induce oocyte maturation in C. tarichi. The levels of 17alpha,20beta,21-trihydroxyprogesterone (20beta-S), progesterone (P), 17alpha-hydroxyprogesterone (17alpha-HOP), 11-deoxycortisol (11-DOC), and 17alpha-hydroxy-20beta-dihydroprogesterone (17,20beta-P) were measured in fish caught from Lake Van and the Karasu River, and injected with human chorionic hormone (hCG) (1,000 and 1,500 IU/kg). Oocytes of fish caught from the lake were also incubated in vitro with different doses (50, 200, and 1,000 ng/ml) of 20beta-S, 17alpha-HOP, 11-DOC, and 17,20beta-P. 11-DOC was found to be the most effective hormone among those measured for inducing oocyte maturation in vivo and in vitro. 17,20beta-P could not be determined in the plasma of any fish in vivo (P < 0.05). 1,000 IU/kg dose of hCG given by injection caused a statistically significant increase in all plasma hormone levels (P < 0.05). It was found that there was a significant decrease in the P level only at 1,500 IU/kg dose of hCG injected (P < 0.05), while the level of other hormones increased at this dose (P < 0.05). It was also determined that all the hormones were effective in germinal vesicle breakdown (GVBD) in in vitro oocyte culture (P < 0.05). However, 11-DOC was found to be the most effective hormone in GVBD at a dose of 200 ng/ml (70% GVBD). In conclusion, 11-DOC synthesized during final oocyte maturation in C. tarichi was found to be a potent inducer of GVBD, which shows that 11-DOC may be described as an oocyte maturation steroid in this species.
塔里奇欧白鲑是一种特有的鲤科鱼类，生活在土耳其安纳托利亚东部的凡湖流域。本研究旨在确定哪些激素可诱导塔里奇欧白鲑的卵母细胞成熟。对从凡湖和卡拉苏河捕获的、注射了人绒毛膜促性腺激素（hCG）（1000和1500国际单位/千克）的鱼，检测了17α,20β,21-三羟基孕酮（20β-S）、孕酮（P）、17α-羟基孕酮（17α-HOP）、11-脱氧皮质醇（11-DOC）和17α-羟基-20β-双氢孕酮（17,20β-P）的水平。从湖中捕获的鱼的卵母细胞还与不同剂量（50、200和1000纳克/毫升）的20β-S、17α-HOP、11-DOC和17,20β-P进行了体外孵育。在体内和体外诱导卵母细胞成熟的检测激素中，发现11-DOC是最有效的激素。在任何鱼的体内血浆中均未检测到17,20β-P（P<0.05）。注射1000国际单位/千克剂量的hCG使所有血浆激素水平有统计学显著升高（P<0.05）。发现仅在注射1500国际单位/千克剂量的hCG时，P水平有显著下降（P<0.05），而此剂量下其他激素水平升高（P<0.05）。还确定所有激素在体外卵母细胞培养中对生发泡破裂（GVBD）均有效（P<0.05）。然而，发现11-DOC在200纳克/毫升剂量时是GVBD中最有效的激素（70%GVBD）。总之，发现在塔里奇欧白鲑最终卵母细胞成熟过程中合成的11-DOC是GVBD的有效诱导剂，这表明11-DOC在该物种中可被描述为一种卵母细胞成熟类固醇。
