丘脑下部促黄体素释放激素类似物(LRH-A)的作用机制 Ⅲ.对罗非鱼脑垂体促性腺激素分泌细胞超微结构的影响

前文(方永强等,1981)探讨了罗非鱼脑垂体促性腺细胞的生理活动与雌鱼性腺发育不同时期的相互关系,对比注射LRH-A后2、4和10小时对促性腺细胞的影响。根据促性腺细胞核的形态和细胞质中分泌颗粒数量的变化,以及DNA、RNA、酸碱性蛋白和酸碱性磷酸酶等一系列反应,初步阐明了LRH-A的作用机制与细胞核和细胞质的代谢变化有关。在此基础上,本文较详细观察了LRH-A对垂体促性腺细胞超微结构的影响,目的在于从亚细胞的水平上,进一步了解其作用机制。

ON THE MECHANISM OF THE ACTION OF HYPOTHALAMIC LUTEINIZING HORMONE-RELEASING HORMONE ANALOGUE (LRH-A)III.ITS EFFECT ON THE ULTRASTRUCTURE OF THE GONADOTROPHIC CELLS OF THE PITUITARY GLAND OF TILAPIA MOSSAMBICA

This paper demonstrates that there is only one kind of gonadotroph in the pituitary gland of Tilapia mossambica, which contains two kinds of secretory granules, the big and the small granules, the former measuring 224 nm and the latter 119 nm in diameter. These pituitary gonadotrophs are evidently the target cells of the hypothalamie releasing hormone.The electron micrographs show that the secretory and the synthetic activities of the gonadotrophic cells are not synchronized. The nonapetiele LRH-A enhances not only the secretory activities of the gonadotrophs but also their synthesis of gonadotropic hormone. The results also show that the action of LRH-A depends very much on the physiological state of the pituitary gland. Stimulation of the LRH-A promotes the secretory activity during the rest phase and enhancement of synthetic activity at the secretory stage.