Pituitary LH responsiveness to GnRH in vitro as related to GnRH receptor number.
Pituitary LH responsiveness to GnRH in vitro as related to GnRH receptor number.
复制标题
体外垂体 LH 对 GnRH 的反应与 GnRH 受体数量有关。
DOI：
10.1152/ajpendo.1984.247.5.e651
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发表时间：
1984
期刊：
影响因子：
--
通讯作者：
Marshall,JC
中科院分区：
文献类型：
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作者：
Baldwin,DM;Bourne,GA;Marshall,JC
本体外研究的目的是确定促性腺激素释放激素（GnRH）的双相促黄体生成激素（LH）反应的增强相的增加以及雌二醇（E2）对其的增强是否与GnRH刺激的垂体GnRH受体浓度增加相关。用GnRH（12 ng/h）持续灌注72 h去卵巢（OVX）、OVX + E2或动情前期大鼠的垂体。每隔10分钟测量LH释放，并在添加GnRH后0、40、80、120和240分钟评估垂体GnRH结合能力（GnRH-BC）。所有给药组均表现出LH释放的双相模式;初始（20-70 min）和增强（120-240 min）的LH分泌（微克/小时）平均速率分别为1.78和3.92（OVX）、6.40和16.67（OVX + E2）以及2.79和18.64（发情前期）。OVX + E2组和动情前期组的总LH释放量（44.0和45.8 μ g）显著高于OVX组（12.4 μ g）。在整个GnRH输注期间，除OVX组在GnRH输注后80 min时出现一过性小幅下降外，所有治疗组的GnRH-BC均未发生显著变化。在输注GnRH后的任何时间，治疗组之间的GnRH-BC均无显著差异。这些结果表明，急性和增强阶段的GnRH刺激LH释放和E2增强这种双相反应的发生独立的任何增加GnRH-BC，并建议这些事件是由受体后机制介导的。
The objective of this in vitro study was to determine whether the increase in the augmented phase of the biphasic luteinizing hormone (LH) response to gonadotrophin-releasing hormone (GnRH) and its enhancement by estradiol (E2) were associated with GnRH-stimulated increases in pituitary GnRH receptor concentration. Pituitary glands from 72 h ovariectomized (OVX), OVX + E2, or proestrous rats were perifused continuously with GnRH (12 ng/h). LH release was measured at 10-min intervals, and pituitary GnRH-binding capacity (GnRH-BC) was assessed at 0, 40, 80, 120, and 240 min after addition of GnRH. All treatment groups exhibited a biphasic pattern of LH release; initial (20-70 min) and augmented (120-240 min) mean rates of LH secretion (micrograms/h) were 1.78 and 3.92 (OVX), 6.40 and 16.67 (OVX + E2), and 2.79 and 18.64 (proestrus), respectively. Total LH release was significantly greater in the OVX + E2 and proestrous groups (44.0 and 45.8 micrograms) vs. the OVX group (12.4 micrograms). Throughout the GnRH infusion period, GnRH-BC did not change significantly in any of the treatment groups with the exception of the OVX group in which there was a transient small decrease at 80 min post-GnRH infusion. There were no significant differences between treatment groups in GnRH-BC at any time after infusion of GnRH. These results demonstrate that the acute and augmented phases of GnRH-stimulated LH release and the enhancement of this biphasic response by E2 occurs independent of any increase in GnRH-BC and suggest that these events are mediated by postreceptor mechanisms.