Gallardo María G P, Chiocchio Sara R, Tramezzani Juan H
Instituto de Neurobiología, Serrano 669, 1414 Buenos Aires, Argentina.
Brain Res. 2004 Dec 24;1030(1):152-8. doi: 10.1016/j.brainres.2004.10.005.
The present research was carried out to study the distribution of melanin-concentrating hormone (MCH) fibers in the median eminence of rats and to evaluate if changes in the MCH content of the median eminence could be related to the release of LHRH. Immunocytochemical studies in the median eminence of males and estrous females showed the presence of MCH fibers, mainly in its internal layer. Diestrous and proestrous animals displayed MCH immunoreactivity in both the internal and external layers of the median eminence. Longitudinal sections of the median eminence in proestrous animals showed that MCH-immunoreactive (ir) density is higher at 12 than at 9 h in both layers of the median eminence. MCH was assayed by radioimmunoassay in median eminences of males and in females in all stages of the estrous cycle at 10 h. It was observed that the content of MCH at diestrus-1 and -2 was higher than in estrus and in male rats. In the day of proestrus, MCH and LHRH were assayed at 10, 12, 13, 14, 15 and 17 h. At 12 h, the content of MCH and LHRH showed the maximal values. At 13 h, MCH content showed a decline, while LHRH was still high. At 14 h, the LHRH content started to decrease. The present results suggest that MCH is involved in the regulation of LHRH release in the female rat.
本研究旨在探讨大鼠正中隆起中黑色素浓集激素（MCH）纤维的分布，并评估正中隆起中MCH含量的变化是否与促性腺激素释放激素（LHRH）的释放有关。对雄性和处于动情期雌性大鼠正中隆起的免疫细胞化学研究显示，MCH纤维主要存在于其内层。处于动情间期和动情前期的动物在正中隆起的内、外层均显示出MCH免疫反应性。动情前期动物正中隆起的纵切片显示，在正中隆起的两层中，MCH免疫反应性（ir）密度在12时高于9时。在10时，通过放射免疫分析法对雄性大鼠以及处于动情周期各阶段的雌性大鼠的正中隆起进行MCH检测。观察到，在动情间期1和动情间期2时MCH的含量高于动情期和雄性大鼠。在动情前期当天，在10、12、13、14、15和17时对MCH和LHRH进行检测。在12时，MCH和LHRH的含量显示出最大值。在13时，MCH含量下降，而LHRH仍处于较高水平。在14时，LHRH含量开始下降。目前的结果表明，MCH参与雌性大鼠LHRH释放的调节。
