Soga T, Sakuma Y, Parhar I S
Department of Physiology, Nippon Medical School, Sendagi-1-1-5, Bunkyo-ku, Tokyo 113-8602, Japan.
Brain Res Mol Brain Res. 1998 Sep 18;60(1):13-20. doi: 10.1016/s0169-328x(98)00153-3.
The purpose of the present study was to examine the regulation of three molecular variants of gonadotropin-releasing hormone (GnRH)-encoding mRNAs by testosterone in the male tilapia Oreochromis niloticus. Tilapias castrated for two weeks were injected intraperitoneally with sesame oil or 5 microgram/g testosterone for 7 days. In situ hybridization histochemistry was performed using 35S-labelled 30-mer antisense oligonucleotide probes complementary to exon two (bases 1-30) of salmon-, seabream-, and chicken II-GnRH. Computerized image analysis was performed to quantify GnRH mRNA expression in the terminal nerve ganglia (nucleus olfactoretinalis) and in individual cells of the preoptic area and the midbrain tegmentum. Testosterone treatment significantly elevated terminal nerve salmon-GnRH mRNA, reduced preoptic seabream-GnRH mRNA but had no effect on midbrain chicken II-GnRH mRNA levels. The total number and size of preoptic and midbrain GnRH mRNA-containing neurons or the total volume of the terminal nerve ganglia in testosterone-treated animals did not differ significantly from oil-treated animals. The midbrain chicken II-GnRH neurons are not targets of testosterone. These results demonstrate for the first time differential regulation of subpopulations of GnRH neurons with molecular diversity and different topography.
本研究的目的是检测睾酮对雄性尼罗罗非鱼促性腺激素释放激素（GnRH）编码mRNA的三种分子变体的调控作用。将阉割两周的罗非鱼腹腔注射芝麻油或5微克/克睾酮，持续7天。使用与鲑鱼、海鲷和鸡II - GnRH外显子二（第1 - 30个碱基）互补的35S标记的30聚体反义寡核苷酸探针进行原位杂交组织化学。进行计算机图像分析以量化终末神经节（嗅视网膜核）以及视前区和中脑被盖单个细胞中GnRH mRNA的表达。睾酮处理显著提高了终末神经中鲑鱼GnRH mRNA的水平，降低了视前区海鲷GnRH mRNA的水平，但对中脑鸡II - GnRH mRNA水平没有影响。睾酮处理动物的视前区和中脑含GnRH mRNA的神经元总数和大小，或终末神经节的总体积与油处理动物相比无显著差异。中脑鸡II - GnRH神经元不是睾酮的作用靶点。这些结果首次证明了具有分子多样性和不同拓扑结构的GnRH神经元亚群的差异调控。
