Expression of estrogen receptors in the hypothalamo-pituitary-ovarian axis in middle-aged rats after re-instatement of estrus cyclicity
Expression of estrogen receptors in the hypothalamo-pituitary-ovarian axis in middle-aged rats after re-instatement of estrus cyclicity
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DOI：
10.1007/s10522-009-9230-6
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发表时间：
2010-02-01
期刊：
影响因子：
4.5
通讯作者：
Jarry, H.
中科院分区：
文献类型：
--
作者：
Boettner, M.;Leonhardt, S.;Jarry, H.
在生殖衰老过程中，雌性大鼠进入持续发情(PE)的无排卵状态。在中年PE大鼠再动情周期的动物模型上，12：00注射孕酮(孕酮0.5 mg/kg体重)，连续4天，对照组注射玉米油。在最后一次注射后，于13：00和17：00对动物进行分析。以青年规律骑行大鼠为阳性对照，分别在发情前期13：00和17：00进行评定。中年PE大鼠的孕酮治疗导致黄体生成素(LH)、卵泡刺激素(FSH)和催乳素(PRL)在一组动物中出现激增，这些动物被称为反应者。中年大鼠视前区ER-βmRNA表达下降，与青年大鼠相似。在下丘脑内侧基底区，只有幼年大鼠ER-αmRNA表达下降。在孕酮反应的大鼠和幼年动物中，观察到脑垂体ER-αmRNA水平的降低。青年规律性运动大鼠ER-βmRNA表达降低。孕酮治疗后，PE大鼠和幼年大鼠卵巢ER-βmRNA水平均降低。综上所述，我们的数据显示，周期给药孕酮可以恢复正常的老年女性的排卵周期，这些女性已经失去了显示自发周期的能力。这种治疗会导致排卵前的黄体生成素、卵泡刺激素和催乳素激增，并伴随着下丘脑、垂体和卵巢中ER的不同调制。
During reproductive aging female rats enter an anovulatory state of persistent estrus (PE). In an animal model of re-instatement of estrus cyclicity in middle-aged PE rats we injected the animals with progesterone (0.5 mg progesterone/kg body weight) at 12:00 for 4 days whereas control animals received corn oil injections. After the last injection animals were analyzed at 13:00 and 17:00. Young regular cycling rats served as positive controls and were assessed at 13:00 and 17:00 on proestrus. Progesterone treatment of middle-aged PE rats led to occurrence of luteinizing hormone (LH), follicle stimulating hormone (FSH), and prolactin surges in a subset of animals that were denoted as responders. Responding middle-aged rats displayed a reduction of ER-beta mRNA in the preoptic area which was similar to the effect in young rats. Within the mediobasal hypothalamus, only young rats showed a decline of ER-alpha mRNA expression. A decrease of ER-alpha mRNA levels in the pituitary was observed in progesterone-responsive rats and in young animals. ER-beta mRNA expression was reduced in young regular cycling rats. ER-beta mRNA levels in the ovary were reduced following progesterone treatment in PE rats and in young rats. Taken together our data show that cyclic administration of progesterone reinstates ovulatory cycles in intact aging females which have already lost their ability to display spontaneous cyclicity. This treatment leads to the occurrence of preovulatory LH, FSH and prolactin surges which are accompanied by differential modulation of ERs in the hypothalamus, the pituitary and the ovary.