GnRH 相关肽在啮齿类前脑及下丘脑分布的免疫组织化学研究

IMMUNOHISTOCHEMICAL STUDY ON DISTRIBUTION OF Gn RH-ASSOCIATED PEPTIDE IN THE FOREBRAIN AND HYPOTHALAMUS OF RODENTS

人和大鼠的促性腺激素释放激素原(ProGnRH),由 GnRH 和 GnRH 相关肽(GAP)组成。本文应用3种分别抗人和大鼠 GAP N-末端、中段和 C-末端的抗血清和 ABC 免疫酶法,对大鼠、小鼠和豚鼠脑 GAP 神经元进行了观察。3种动物的 GAP 神经元分布相似,GAP 神经元胞体主要存在于隔-视前区,以终板血管器附近的斜角带最为集中。视上核附近亦有较多的 GAP神经元。GAP 纤维广泛存在于前脑和下丘脑,终止于终板血管器和正中隆起。3种 GAP 抗血清中,以抗 N-末端者染出的免疫反应阳性成分多,染色深。GAP 神经元与相邻切片上所染的 GnRH神经元的胞体、纤维和终末的形态和分布相同。本文的观察和其他有关的研究提示,哺乳类具有相同的 ProGnRH,其加工产物 GAP(或其裂解片段)与 GnRH 共同分泌到垂体门脉,调节垂体前叶的激素分泌。

Gonadotropin-releasing hormone(GnRH)prohormone of human and rat consists of GnRH and GnRH-associated peptide(GAP).In this study,three antisera against N-terminal,mid-region and C-terminal of GAP,and ABC immunoenzyme method were used to observe the GAP neurons in the brains of the rat,mouse and guinea pig.The distribution of GAP neurons in these animals was similar.GAP perikarya were mainly present in the septo-preoptic area,with the largest concentration in the diagonal band near the organum vasculosum of the lamina terminalis.Some GAP perikarya were also seen in the brain area near the supraoptic nucleus.GAP fibers were widely present in the forebrain and hypothalamus,and terminated in the organum vasculosum of lamina terminalis and median eminence.Of 3 GAP antisera,the one against N-terminal gave more immunoreactive elements and more intense staining.The morphology and distribution of GAP perikarya,fibers and terminals were similar to those of GnRH.These results,combined with other related facts,suggest that there is a common GnRH prohormone in mammals,and its processing products,GAP(or cleavage fragments)and GnRH,are cosecreted into hypophysial portal system to regulate anterior pituitary hormone secretion.