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

通过免疫组织化学和超微结构检查了尼罗罗非鱼性腺的神经支配。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平滑肌细胞的表面。细神经束穿过含有生精生殖细胞囊肿的小叶之间的间隙。这些神经纤维的末端还与包围小叶的平滑肌细胞以及产生类固醇的细胞的表面接触。这些观察结果表明，睾丸的神经支配不仅可以控制平滑肌细胞的收缩和舒张，还可以控制类固醇的分泌。在卵巢中，粗大的神经束集中在面向肠系膜一侧的卵巢壁中靠近卵巢动脉和静脉的区域。一些轴突组从粗神经中分出，终止于类固醇产生细胞簇附近，这些细胞分布在卵黄卵母细胞的间质区域。轴突末端与产生类固醇的细胞密切相关。末端含有许多透明囊泡、一些致密核囊泡和一些线粒体。此外，在卵黄卵母细胞周围产生类固醇的卵泡膜细胞表面观察到一些末端。我们对类固醇生成细胞直接神经支配的观察揭示了调节罗非鱼卵巢中类固醇生成的可能新途径。

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.