Diurnal rhythmicity of beta-1- and beta-2-adrenergic receptors in ovariectomized, ovariectomized estradiol-treated and proestrous rats.
Diurnal rhythmicity of beta-1- and beta-2-adrenergic receptors in ovariectomized, ovariectomized estradiol-treated and proestrous rats.
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卵巢切除、卵巢切除雌二醇处理和发情前期大鼠中β-1-和β-2-肾上腺素能受体的昼夜节律性。
DOI：
10.1159/000125295
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发表时间：
1989
影响因子：
4.1
通讯作者：
Wise,PM
中科院分区：
文献类型：
--
作者：
Weiland,NG;Wise,PM
去甲肾上腺素对LH的影响是复杂的：卵巢类固醇环境似乎决定去甲肾上腺素是刺激还是抑制LH分泌。有人提出，类固醇通过改变下丘脑中α1-（刺激性）和β-（抑制性）肾上腺素能受体的相对浓度，使去甲肾上腺素对LH产生相反的作用。因此，许多研究者认为，雌二醇可能通过增加下丘脑一个或多个关键区域中α1-肾上腺素能受体的密度和降低β-肾上腺素能受体的密度，允许去甲肾上腺素刺激LH释放。为了具体地检验这一假设，我们在一天中的不同时间测量了动情前期、去卵巢和去卵巢雌二醇处理的大鼠的β1和β2肾上腺素能受体密度，以确定（1）β受体密度是否表现出昼夜节律性，（2）在LH分泌增加时β受体是否减少和/或（3）类固醇环境如何影响受体密度和/或受体密度节律。在某些脑区，β1和β2受体的密度呈现昼夜节律。这些节律仅在发情前期和卵巢切除大鼠中可检测到，并且仅在选定的脑区域中。雌激素治疗在不同的大脑区域有相反的效果。它抑制去卵巢大鼠β1受体浓度的节律，也抑制视交叉上核和松果体中受体的平均密度。相反，雌激素增加内侧视前核中β1受体的密度。总之，本研究的结果表明，β受体的昼夜节律和雌二醇的作用与先前报道的受体介导的功能变化相关。此外，他们揭示了一天中的时间和类固醇环境对不同脑区β1和β2受体密度的复杂相互作用。最后，数据强烈表明β受体密度的降低不能解释动情前期或雌二醇诱导的LH峰的时间或去甲肾上腺素抑制卵巢切除大鼠LH释放或刺激类固醇治疗大鼠LH释放的能力。
The effect of norepinephrine on LH is complex: the ovarian steroidal milieu appears to determine whether norepinephrine stimulates or inhibits LH secretion. It has been proposed that steroids allow norepinephrine to have opposite effects on LH by altering the relative concentrations of α1-(stimulatory) and β-(inhibitory) adrenergic receptors in the hypothalamus. Thus, many investigators have argued that estradiol may permit norepinephrine to stimulate LH release by increasing the density of α1- and decreasing the density of β-adrenergic receptors in one or more key hypothalamic regions. To test this hypothesis specifically, we measured the density of β1- and β2-adrenergic receptor densities in proestrous, ovariectomized, and ovariectomized estradiol-treated rats at various times of day to determine (1) whether the densities of β-receptors exhibit diurnal rhythmicity, (2) whether β-receptors decrease during the time of increased LH secretion and/or (3) how steroidal milieu influences the density and/or the rhythm of receptor densities. The densities of β1- and β2-receptors exhibit a diurnal rhythm in some brain areas. These rhythms are detectable only in proestrous and ovariectomized rats and only in selected brain regions. Estrogen treatment has opposing effects in different brain regions. It suppresses the rhythm of β1-receptor concentrations in ovariectomized rats and also suppresses the average density of receptors in the suprachiasmatic nucleus and pineal gland. In contrast, estrogen increases the density of β1-receptors in the medial preoptic nucleus. In summary, the results of this study demonstrate that the diurnal rhythm in β-receptors and the effect of estradiol correlate with previously reported changes in receptor-mediated functions. In addition, they reveal the complex interactions of time of day and steroidal milieu on the density of β1- and β2-receptors in various brain regions. Finally, the data strongly suggest that decreases in the densities of β-receptors cannot explain the timing of the proestrous or estradiol-induced LH surge or the ability of norepinephrine to inhibit LH release in ovariectomized rats or stimulate LH release in steroid-treated rats.