Orexin A and B levels in the hypothalamus of female rats: the effects of the estrous cycle and age
Orexin A and B levels in the hypothalamus of female rats: the effects of the estrous cycle and age
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DOI：
10.1530/eje.0.1500737
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发表时间：
2004-05-01
影响因子：
5.8
通讯作者：
Stenberg, D
中科院分区：
文献类型：
--
作者：
Porkka-Heiskanen, T;Kalinchuk, A;Stenberg, D
目的：食欲素参与包括生殖在内的多种生理功能的调节。能量平衡和警觉状态。为了成功繁殖，发情周期中精确计时的荷尔蒙分泌必须与适当的营养和警惕状态相结合。促生长素对LH释放的类固醇和营养状态依赖性调节，以及警惕性的提高，表明促生长素可能在发情周期过程中协调这些功能。设计：我们研究了中青年大鼠在发情周期过程中脑组织中食欲素的水平。年轻的周期大鼠（3个月大）和不规律/非周期大鼠（7-9个月大）检查阴道涂片和血清激素水平。方法：测定不同发情周期下丘脑和外侧下丘脑中食欲素A、B的组织浓度。结果：光照后5 ~ 6 h，幼龄周期大鼠下丘脑Orexin A浓度明显高于同期其他周期；发情前期和发情后期食欲素B浓度均高于发情后期。未骑车的中年大鼠在发情前期和发情期下丘脑中食欲素A和B的浓度均低于骑车大鼠。结论：发情当日下丘脑的高促食欲素浓度可能导致黄体生成素和催乳素激增。高食欲素A水平也可能导致发情当天睡眠时间减少。
Objective: Orexins have been implicated in the regulation of several physiological functions including reproduction. energy balance and vigilance state. For successful reproduction, the precisely timed hormonal secretions of the estrous cycle must be combined with appropriate nutritional and vigilance states. The steroid- and nutritional state-dependent modulation of LH release by orexins, as well as an increase of vigilance, suggest that orexins may co-ordinate these functions in the course of the estrous cycle.Design: We studied the brain tissue levels of orexins in the course of the estrous cycle in young and middle-aged rats. Young cycling rats (3 months old) and irregularly/non-cycling (7-9 months old) female rats were inspected for vaginal smears and serum hormone levels.Methods: Tissue concentrations of orexin A and B were measured in the hypothalamus and lateral hypothalamus on different days of the estrous cycle.Results: Orexin A concentration in the hypothalamus of young cycling rats was higher on the day of proestrus 5 - 6 h after the lights were switched on than on the other days of the estrous cycle at the same circadian time. Orexin B concentration was higher on both the day of proestrus and the day of estrus as compared with the days of diestrus. The hypothalamic concentrations of both orexin A and B in the non-cycling middle-aged rats were lower than those in cycling rats on the days of proestrus and estrus.Conclusions: We have concluded that the high hypothalamic concentration of orexins on the day of proestrus may contribute to the LH and prolactin surges. High orexin A levels may also contribute to the decreased amount of sleep on the day of proestrus.