A priming effect of luteinizing hormone releasing factor on the anterior pituitary gland in the female rat.
A priming effect of luteinizing hormone releasing factor on the anterior pituitary gland in the female rat.
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黄体生成素释放因子对雌性大鼠垂体前叶的启动作用。
DOI：
10.1677/joe.0.0620573
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发表时间：
1974
期刊：
影响因子：
--
通讯作者：
G. Fink
中科院分区：
文献类型：
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作者：
M. Aiyer;S. Chiappa;G. Fink
黄体生成素释放因子 (LH-RF) 不仅可以刺激黄体生成素 (LH) 的分泌，而且还具有启动垂体前叶的能力，因此进一步暴露于 LH-RF 可以增强促性腺激素的反应性，这一可能性已被研究。连续两次静脉注射的效果在用戊巴比妥钠麻醉的大鼠中测定注射相同剂量的LH-RF（50ng/100g体重）对血浆中LH浓度的影响。在注射 LH-RF 之前和之后每隔一段时间从颈外静脉采集血样，并通过放射免疫测定法测量 LH 的血浆浓度以及某些样本中的卵泡刺激素 (FSH) 浓度。在发情前 13.30 小时用戊巴比妥钠麻醉大鼠并静脉注射。连续两次注射 LH-RF，间隔时间为 30、60、120 或 240 分钟，第二次注射的 LH 反应明显大于第一次注射。当两次给药间隔 60 分钟时，LH 反应最大。第一次注射 60 分钟后第二次注射 LH-RF 的 FSH 反应与第一次注射没有显着差异。与发情前相比，LH-RF在发情中期和发情间期的启动作用要小得多，并且在发情时不能表现出来。间情期早上的卵巢切除术降低了对在发情前下午间隔 60 分钟第一次和第二次注射 LH-RF 的 LH 反应，这种效应在卵巢切除术后不久注射苯甲酸雌二醇部分逆转。这些发现与在发情中期施用苯甲酸雌二醇增加了在发情期间LH-RF的启动效应的幅度的事实一起表明，发情前的反应取决于血浆雌二醇-17\g=b\的升高，其在发情前的早晨达到峰值。虽然雌激素在确定 LH-RF 启动效应的大小方面起着重要作用，但似乎卵巢或肾上腺分泌的类固醇都不会介导这种效应，因为 LH 对注射两剂 LH-RF 的反应的概况和强度 Department of Human Anatomy, South Parks Road, Oxford, 0X1 3QX
The possibility that luteinizing hormone releasing factor (LH-RF) not only stimulates the secretion of luteinizing hormone (LH) but also has the ability to prime the anterior pituitary gland so that further exposure to LH-RF enhances the responsiveness of the gonadotrophs has been investigated. The effect of two successive i.v. injections of the same dose of LH-RF (50 ng/100 g body weight) on the concentration of LH in plasma was determined in rats anaesthetized with sodium pentobarbitone. Blood samples were collected from the external jugular vein immediately before and at frequent intervals after the injections of LH-RF, and plasma concentrations of LH and, in some samples, follicle-stimulating hormone (FSH) were measured by radioimmunoassay. In rats anaesthetized with sodium pentobarbitone at 13.30 h ofpro-oestrus and injected i.v. with two successive doses of LH-RF, separated by an interval of 30, 60, 120 or 240 min, the LH response to the second injection was significantly greater than that to the first. The LH response was greatest when the two doses were separated by an interval of 60 min. The FSH response to the second injection of LH-RF given 60 min after the first was not significantly different from that to the first injection. Compared with pro-oestrus, the priming effect of LH-RF was much less at metoestrus and dioestrus, and could not be demonstrated at oestrus. Ovariectomy on the morning of dioestrus reduced the LH responses to the first and second injections of LH-RF given 60 min apart on the afternoon of pro-oestrus, an effect which was partially reversed by administration of oestradiol benzoate shortly after ovariectomy. These findings together with the fact that administration of oestradiol benzoate at metoestrus increased the magnitude of the priming effect of LH-RF at dioestrus suggest that the response at pro-oestrus is dependent upon the rise in plasma oestradiol-17\g=b\ which reaches a peak on the morning of pro-oestrus. Although oestrogen plays an important role in determining the magnitude of the priming effect of LH-RF, it appears that none of the steroids secreted by either the ovaries or the adrenal glands mediates this effect since the profile and magnitude of the LH responses to the two doses ofLH-RF injected Department of Human Anatomy, South Parks Road, Oxford, 0X1 3QX