Lewis C E, Richards P S, Morris J F
Department of Human Anatomy, University of Oxford.
J Mol Endocrinol. 1989 Jan;2(1):55-63. doi: 10.1677/jme.0.0020055.
Protein kinase C (PK-C) has been implicated in the action of LHRH because LHRH-induced release of LH is partially mimicked by phorbol esters which activate PK-C, and reduced in magnitude by inhibitors of PK-C. We have used a reverse haemolytic plaque assay for LH to visualize and compare the direct effects on individual rat gonadotrophs of (1) a 2-h exposure to a range of concentrations of LHRH and phorbol 12-myristate 13-acetate (PMA) and (2) a single maximally stimulatory dose (10 nM) of LHRH or PMA, or LHRH in the presence of inhibitors of PK-C (retinal and isoquinolone sulphonamide; H7) over six consecutive 30-min intervals. Quantitative analysis of the size and number of haemolytic plaques indicated that LHRH induced a dose- and time-dependent increase in the amount of LH release by individual gonadotrophs, with no evidence of the priming effect of LHRH. Stimulation by 10nM LHRH induced recruitment of actively secreting gonadotrophs which reached maximum levels by 90 min. There was a delay of 90-120 min before 10 nM PMA caused a significant release of LH, as assessed by both the size and number of plaques. During the first 30 min of exposure, the presence of 10 microM retinal or H7 augmented LHRH-induced secretion of LH, with the absence of any inhibition of the effects of LHRH until 90-120 min, when both the size and number of plaques were reduced compared with those formed in the presence of LHRH alone.(ABSTRACT TRUNCATED AT 250 WORDS)
蛋白激酶C（PK-C）与促性腺激素释放激素（LHRH）的作用有关，因为佛波酯可模拟LHRH诱导的促黄体生成素（LH）释放，而佛波酯能激活PK-C，且PK-C抑制剂可降低其释放量。我们采用反向溶血空斑试验检测LH，以可视化并比较以下因素对单个大鼠促性腺激素细胞的直接影响：（1）2小时内暴露于一系列浓度的LHRH和佛波醇12-肉豆蔻酸酯13-乙酸酯（PMA）；（2）单一最大刺激剂量（10 nM）的LHRH或PMA，或在PK-C抑制剂（视网膜和异喹啉磺酰胺；H7）存在的情况下，连续六个30分钟间隔给予LHRH。对溶血空斑大小和数量的定量分析表明，LHRH诱导单个促性腺激素细胞释放LH的量呈剂量和时间依赖性增加，且无LHRH的预激效应证据。10 nM LHRH刺激可诱导活跃分泌的促性腺激素细胞募集，90分钟时达到最高水平。10 nM PMA导致LH显著释放存在90 - 120分钟的延迟，这通过空斑大小和数量评估得出。在暴露的前30分钟，10 μM视网膜或H7的存在增强了LHRH诱导的LH分泌，直到90 - 120分钟才出现对LHRH效应的抑制，此时空斑大小和数量与仅存在LHRH时相比均减小。（摘要截短于250字）
