Innervatiuon of steroid-producing cells in the gonads of fish.

免疫组织化学和超微结构研究了尼罗提鱼性腺的神经支配。在睾丸中，许多粗大的神经束分布在传出管周围的壁上。神经元似乎终止于传出管壁的平滑肌细胞表面。细神经束穿过含有生精生殖细胞囊的小叶间隙。这些神经纤维的末端也与包裹小叶的平滑肌细胞和类固醇细胞的表面接触。这些观察结果表明，睾丸的神经支配可能不仅控制平滑肌细胞的收缩和松弛，而且还控制类固醇的分泌。卵巢面向肠系膜一侧，粗神经束位于卵巢壁动脉和静脉附近。几个轴突群从粗神经分叉，并终止于分布在卵黄卵母细胞间质区域的类固醇细胞群附近。轴突终末与类固醇产生细胞关系密切。末端有许多透明的小泡，少量密包的小泡和一些线粒体。此外，在卵黄卵母细胞周围产生类固醇的卵泡细胞表面观察到一些终端。我们对类固醇产生细胞的直接神经支配的观察为罗非鱼卵巢中类固醇产生的调节提供了一条可能的新途径。

The innervation of the gonads of Oreochromis niloticus examined immunohistochemically and ultrastructurally. In testis, many thick nerve bundles are distributed in the wall surrounding the efferent duct. The neurons appear to terminate at the surface of smooth muscle cells in the efferent duct wall. Thin nerve bundles penetrate the interstices among lobules containing cysts of spermatogenic germ cells. terminal ends of these nerve fibers also make contact with smooth muscle cells enclosing lobules and with the surface of steroid-producing cells. These observations suggest that innervation of the testis may not only control the contracting and relaxing of smooth muscle cells but also control steroid secretion. In ovary, thick nerve bundles were localized in the area near the ovarian artery and vein in the ovarian wall on the side facing the mesentery. Groups of a few axons ramified from the thick nerves and were terminated in the proximity of clusters of steroid-producing cells which are distributed in the interstitial area among yolky oocytes. The axon terminals were in intimate relation with the steroid-producing cells. The terminals contained many clear vesicles, a few dense-cored vesicles and some mitochondria. Moreover, a few terminals were observed on the surface of steroid-producing theca cells surrounding yolky oocytes. Our observations of direct innervation of steroid-producing cells bring to light a possible new avenue for regulation of steroid production in the tilapia ovary.