BIPHASIC EFFECTS OF ESTROGEN ON GONADOTROPIN-RELEASING HORMONE-INDUCED LUTEINIZING-HORMONE RELEASE IN MONOLAYER-CULTURES OF RAT AND MONKEY PITUITARY-CELLS
BIPHASIC EFFECTS OF ESTROGEN ON GONADOTROPIN-RELEASING HORMONE-INDUCED LUTEINIZING-HORMONE RELEASE IN MONOLAYER-CULTURES OF RAT AND MONKEY PITUITARY-CELLS
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DOI：
10.1210/endo-114-2-659
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发表时间：
1984-01-01
期刊：
影响因子：
4.8
通讯作者：
NEILL, JD
中科院分区：
文献类型：
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作者：
FRAWLEY, LS;NEILL, JD
在大鼠垂体细胞的单层培养中，雌激素对促黄体生成素分泌的负反馈效应一直难以证实。建立了表现这种反应所需的实验条件，并在此过程中建立了研究类固醇对垂体细胞作用的模型。实验采用了动态和静态孵育系统。灌注实验中，随机取大鼠发情周期各阶段胰蛋白酶分散的垂体细胞，用聚l -赖氨酸贴于玻璃罩上，孵育48 h，然后装于赛克斯-摩尔室。在每个实验中，同时灌注2个腔室：一个腔室中含有1.8倍的培养基。10-10 m17。-雌二醇和另一个单独使用中。促性腺激素释放激素（GnRH）（4.2倍）；每小时共输注5分钟（10-9 M），收集渗滤液样品，每隔5分钟进行LH测定。与对照组相比，雌激素治疗显著（P < 0.01）抑制了前5次GnRH脉冲的LH释放。这种抑制在灌注早期最明显，但在6小时后消失。雌二醇对大鼠垂体细胞单层培养中gnrh诱导的LH释放有一种有效但短暂的抑制作用。在随后的一组实验中，对静态培养系统进行了修改，以依次评估雌激素对同一组细胞中LH释放的双相影响。将42小时前培养的大鼠垂体细胞同时用17. β处理3小时。-雌二醇（3.7倍）10-10 M)和不同浓度的GnRH(5。10-10到1倍。10-7 M)测量类固醇对LH分泌的抑制作用。在类固醇暴露27小时后，在相同的细胞上重复该实验，以评估雌激素对LH释放的促进作用。在静态培养的大鼠垂体中，如果雌激素暴露时间和孵育时间较短，雌激素的负反馈是明显的。同一组细胞可连续使用数日，观察雌激素对黄体生成素分泌的抑制和刺激作用。猴子（猕猴）脑垂体细胞的培养实验也得到了类似的结果。这些发现表明，培养的垂体细胞对雌二醇的双相作用有反应，并证明了两种模型系统对研究这些现象的效用。
The negative feedback effect of estrogen on LH [luteinizing hormone] secretion has been difficult to demonstrate in monolayer cultures of rat pituitary cells. The experimental conditions required for manifestation of this response were established and, in the process, models for investigating the actions of steroids on pituitary cells were developed. Both dynamic and static incubation systems were used. For perfusion experiments, trypsin-dispersed pituitary cells from rats at random stages of the estrous cycle were attached to glass coverslips with poly-L-lysine, incubated for 48 h, and then mounted in Sykes-Moore chambers. In each of these experiments, 2 chambers were perifused concurrently: one with medium containing 1.8 .times. 10-10 M 17.beta.-estradiol and the other with medium alone. GnRH [gonadotropin-releasing hormone] (4.2 .times. 10-9 M) was coinfused for 5 min out of every hour, and samples of perifusate were collected as 5-min fractions for assay of LH. Estrogen treatment significantly (P < 0.01) suppressed LH release in response to the first 5 GnRH pulses compared to the control value. This inhbiition was most pronounced early in the perifusion, but had disappeared by 6 h. Estradiol exerts a potent but transient inhibition of GnRH-induced LH release in monolayer cultures of rat pituitary cells. In a subsequent set of experiments, a static incubation system was modified to assess sequentially the biphasic effects of estrogen on LH release by the same group of cells. Cultures of rat pituitary cells that had been established 42 h previously were treated simultaneously for 3 h with 17.beta.-estradiol (3.7 .times. 10-10 M) and various concentrations of GnRH (5 .times. 10-10 to 1 .times. 10-7 M) to measure the inhibitory effects of the steroid on LH secretion. This experiment was repeated on the same cells after 27 h of steroid exposure to estimate the facilitatory actions of estrogen on LH release. The negative feedback of estrogen was demonstrable in static cultures of rat pituitaries provided that the period of estrogen exposure and duration of incubation were brief. The same groups of cells can be used on consecutive days to investigate the inhibitory and stimulatory effects of estrogen on LH secretion. Experiments with cultures of monkey [Macaca mulatta] pituitary cells yielded similar results. These findings indicate that cultured pituitary cells are responsive to the biphasic actions of estradiol and demonstrate the utility of 2 model systems for investigating these phenomena.