Di Matteo L, Vallarino M, Pierantoni R
Dipartimento di Fisiologia Umana e Funzioni Biologiche Integrate F. Bottazzi, Facoltà di Medicina e Chirurgia, Seconda Università di Napoli, Italy.
J Exp Zool. 1996 Jan 1;274(1):33-40. doi: 10.1002/(SICI)1097-010X(19960101)274:1<33::AID-JEZ4>3.0.CO;2-G.
In the amphibian brain four molecular forms of GnRH have been identified so far: mammalian GnRH (m- and hydroxyproline9m-), chicken II GnRH (cII), and a salmon (s) GnRH-like peptide. In Rana esculenta, cII- and s-GnRH-like molecules have been partially characterized in the brain extracts using HPLC combined with radioimmunoassay. Moreover, since cII-GnRH-like material has been detected in Rana esculenta testis, the present study describes the localization of the above peptides in the brain and testis of the frog. Immunoreactive cII-GnRH and m-GnRH neurons and fibers were identified in the anterior preoptic area (APOA) and in the median septal area (MSA). A population of cells located on the dorsal side of the caudal preoptic region was also stained. Immunopositive fibers were seen to overlap the median eminence before ending within the pars nervosa. Moreover, densely packed fibers made close contact with the vascular complex in the median eminence. Conversely, immunoreactive s-GnRH-like material was absent in APOA and MSA, but weakly scattered elements were detected by the anti-s-GnRH serum in the dorsal side of the caudal preoptic region. Using m-GnRH antiserum, a strong immunopositivity was observed in the median eminence but not within the pars nervosa, indicating that, besides cII-GnRH and s-GnRH-like material, also m-GnRH-like material is present in Rana esculenta brain. In the testis, cells of the interstitial and germinal compartment were detected by anti-cII-GnRH during different periods of the annual cycle. In particular, in October and February interstitial tissue was intensely stained, coinciding with periods of increased androgen production and the onset of the new spermatogenic wave, respectively.
迄今为止，在两栖动物大脑中已鉴定出四种促性腺激素释放激素（GnRH）分子形式：哺乳动物GnRH（m - 和羟脯氨酸9m - ）、鸡II型GnRH（cII）以及一种鲑鱼（s）GnRH样肽。在食用蛙中，已通过高效液相色谱（HPLC）结合放射免疫分析法对大脑提取物中的cII - 和s - GnRH样分子进行了部分特性分析。此外，由于在食用蛙睾丸中检测到了cII - GnRH样物质，本研究描述了上述肽在蛙脑和睾丸中的定位。在前视前区（APOA）和正中隔区（MSA）鉴定出了免疫反应性cII - GnRH和m - GnRH神经元及纤维。位于视前尾区背侧的一群细胞也被染色。免疫阳性纤维在神经垂体部内终止之前与正中隆起重叠。此外，密集排列的纤维与正中隆起中的血管复合体紧密接触。相反，APOA和MSA中不存在免疫反应性s - GnRH样物质，但抗s - GnRH血清在视前尾区背侧检测到了少量散在的成分。使用m - GnRH抗血清，在正中隆起中观察到强免疫阳性，但在神经垂体部内未观察到，这表明除了cII - GnRH和s - GnRH样物质外，食用蛙脑中也存在m - GnRH样物质。在睾丸中，在年度周期的不同时期，抗cII - GnRH检测到了间质和生精区室的细胞。特别是在10月和2月，间质组织被强烈染色，分别与雄激素产生增加的时期和新的生精波开始的时期一致。
