Effects of endothelin-I on the function of the cultured granulosa sells

本研究旨在探讨内皮素-1（ET-1）是否对猪中小型卵泡颗粒细胞的功能有直接影响。在培养的猪卵泡颗粒细胞中观察到ET-1样免疫反应阳性（ET-1-LI），北方印迹分析证实了前ET-1原的信使RNA在这些细胞中的表达。结合研究表明，结合位点为非选择性的单一类型，主要为ET_B亚型。在刺激卵巢周期患者的卵泡液中检测到ET-1-LI增加。ET-1刺激基础和FSH刺激的孕酮分泌在短期孵育（2小时），而它抑制FSH和hCG刺激的孕酮积累在长期孵育（48小时）的未成熟或中成熟的颗粒细胞。ET-1可明显促进细胞DNA合成。ET-1可能通过cAMP -蛋白激酶A途径和细胞内钙动员-蛋白激酶C途径诱导上述生物学作用。上述结果提示，ET-1对猪颗粒细胞的功能具有自分泌/旁分泌作用，同时也证实了人早孕蜕膜细胞能分泌ET-1，并具有ET-1的特异性受体，其功能与磷脂酰肌醇的降解偶联。提示ET-1可能具有自分泌和/或旁分泌功能。

This study was conducted to investigate whether endothelin-1 (ET-1) has direct effects on the functions of porcine granulosa cells harvested from small or medium follicles. The positive ET-I-like immunoreactivity (ET-1-LI) was observed in the cultured porcine granulosa cells, and Northern blot analysis demonstrated the expression of messenger RNA for prepro-ET-1 in these cells. THe binding study showed the presence of non-selective, single class of binding sites which included subtype of ET_B, predominantly. Increased ET-1-LI was detected in the human follicular fluid obtained from the patients in stimulated ovarian cycles. ET-1 stimulated basal and FSH-stimulated secretion of progesterone during short term incubation (2 hrs), while it inhibited FSH- and hCG-stimulated accumulation of progesterone during long-term incubation (48 hrs) of immature or moderately mature granulosa cells. ET-1 significantly increased DNA synthesis in the cells. These biological actions were induced by ET-1, probably via cAMP - protein kinase A pathway and intracellular calcium mobilization - protein kinase C pathway. The results suggest that ET-1 exerts autocrine/paracrine effects on the porcine granulosa cell functions.Furthermore, the present study also demonstrates that human decidual cells in the early pregnancy can synthsize and release ET-1, and possess specific receptors for ET-1 functionally coupled to phosphoinositide breakdown. This suggests that ET-1 may have its potential autocrine and/or paracrine function in human decidual cells.