催熟技術改善のためのウナギ卵形成機構の解析

在本研究中，研究了反复注射鲑鱼垂体提取物诱导日本鳗鲡卵巢发育过程中与生殖相关的分子的对照。我们对包括11β-羟化酶在内的甾体生成酶的多克隆抗血清进行了表征，以分析胚胎形成前卵母细胞生长的机制。接下来，我们利用卵巢培养系统研究了极低密度脂蛋白（VLDL）和11-酮睾酮（11KT）（一些硬骨鱼的主要雄激素）对油滴积聚到卵黄发生前卵母细胞的影响。体外可诱导卵黄前卵母细胞油滴积累。与VLDL和11KT共同处理导致了显著的油滴积累。这些数据表明，油滴中的脂质至少部分来自VLDL， 11KT在其转移和/或积聚到卵母细胞中起重要作用。一般来说，成熟诱导类固醇（MIS）通过特异性受体（MIS- r）诱导卵母细胞成熟。核孕激素受体（PR）或膜结合孕激素受体（mPR）可能具有MIS-R的功能。我们检测了各种类型的PR和mPR在日本鳗鲡卵巢发育过程中的表达和定位。然而，我们无法将这些PR或mPR识别为misr。此外，我们还研究了日本鳗鲡蛋品质恶化的原因，并指出了这一过程中涉及的各种因素。

In this study, the controls of reproduction-related molecules were examined during ovarian development induced by repeated injections of salmon pituitary extract in the Japanese eel, Anguilla japonica. We characterized polyclonal antisera of steroidogenic enzymes including 11β-hydroxylase to analyze the mechanism of previtellogenic oocyte growth. In the next, we examined the effects of very low density lipoprotein (VLDL) and 11-ketotestosterone (11KT), a major androgen in some teleosts, on the accumulation of oil droplets into previtellogenic oocytes using ovarian culture system. Accumulation of oil droplets in previtellogenic oocytes could be induced in vitro. Co-treatment with VLDL and 11KT resulted in significant oil droplet accumulation. These data suggest that lipids in oil droplets originate, at least in part, from VLDL, and that 11KT plays an important role in their transfer and/or accumulation into oocytes. In general, oocyte maturation is induced by the maturation-inducing steroid (MIS) through the specific receptor (MIS-R). Nuclear progestin receptor (PR) or membrane-bound progestin receptor (mPR) may have the function as MIS-R. We examined the expression and localization of various types of PR and mPR during ovarian development in the Japanese eel. However, we could not identify these PR or mPR as MIS-R. In addition, we examined the causes for the deterioration in egg quality in Japanese eel and indicated that various factors involved in the process.