哺乳对母鼠下丘脑GnRH神经元影响的免疫组化研究

IMMUNOHISTOCHEMICAL STUDY OF THE DYNAMIC CHANGES OF GnRH IMMUNOREACTIVE NEUROCOMPONENTS IN RAT HYPOTHALAMUS DURING LACTATION AND AFTER WEANING

采用免疫组织化学方法研究了产后授乳和中断授乳的雌性大鼠下丘脑内促性腺激素释放激素(GnRH)阳性神经元和神经纤维的密度和染色反应的动态变化。在哺乳的第3天,将仔鼠去除,在中断授乳后的第1天～4天,下丘脑内侧隔核、视前内侧区和Broca斜角带内的GnRH阳性神经元胞体的反应强度明显高于继续授乳组。在正中隆起和终板血管器的GnRH阳性纤维密度和染色强度也比授乳组明显增加。结果表明:中断授乳的母鼠下丘脑内GnRH分泌神经元激素的合成和释放功能均明显增强;相反,授乳对下丘脑内GnRH神经元的合成和释放激素的功能有抑制作用。

The dynamic changes of the density and staining intensity of GnRH immunoreactive neurons and fibers in rat hvpotnalanms were studied during lactation and after weaning by immunohistochemical method. The litter was removed on day 3 of lactation, 1-4 days after removel of the litter, the staining intensity of GnRH immunoreactive neurons in medial septal area, medial preoptic area and diagonad band of Broca were generally in- creased. The density and staining intensity of GnRH fibers and terminals in median eminence and organum vasculosum of the lamina terminals were significantly increased. These results indicate that the suckling stimulus exerts an inhibitory effect on both the secretion and the release of GnRH in hypothalamus during lactation. After removal of the litter, the recovery of GnRH secretion and release occurs very rapidly.