Apolipoprotein-E messenger RNA in rat ovary is expressed in theca and interstitial cells and presumptive macrophage, but not in granulosa cells.
Apolipoprotein-E messenger RNA in rat ovary is expressed in theca and interstitial cells and presumptive macrophage, but not in granulosa cells.
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DOI：
10.1210/mend.6.6.1495495
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发表时间：
1992-06
影响因子：
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通讯作者：
Monica;Nicosia;William;H. Moger;Cheryl;A. Dyer;Margaret;M. Prack;David;L. Williams
中科院分区：
文献类型：
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作者：
Monica;Nicosia;William;H. Moger;Cheryl;A. Dyer;Margaret;M. Prack;David;L. Williams
载脂蛋白-E (apoE) 是多种脂蛋白的组成部分，是细胞脂蛋白受体的配体。与大多数载脂蛋白不同，apoE 在外周组织中合成，包括那些参与类固醇生成的组织。肾上腺细胞中的 ApoE 表达抑制胆固醇用于类固醇合成的利用，并阻断通过蛋白激酶 A 途径的信号转导。在培养的卵巢膜/间质细胞中，外源 apoE 已被证明可以抑制 LH 诱导的雄激素合成。这些发现支持 apoE 作为参与调节类固醇生成的自分泌或旁分泌因子的作用。在本研究中，原位杂交用于鉴定在动情周期为 4 天的大鼠、怀孕大鼠、经 PMSG 处理以刺激卵泡发育的未成熟大鼠以及经 PMSG 处理并随后给予 hCG 以刺激排卵和黄体化的大鼠的卵巢中表达 apoE mRNA 的细胞类型。在动情周期所有阶段的动物以及用 PMSG 治疗的未成熟大鼠中，ApoE mRNA 定位于卵泡膜和间质细胞。在卵母细胞、卵丘细胞或颗粒细胞中未检测到 ApoE mRNA。闭锁卵泡和退化黄体中的局部推定巨噬细胞簇也表达高水平的 apoE mRNA。这种复杂的表达模式可能表明 apoE 在大鼠卵巢中具有多种功能。由卵泡膜和间质细胞产生的 ApoE 可能在局部充当自分泌因子来调节雄激素的产生。在闭锁卵泡和退化黄体中产生的 ApoE 可能有助于促进这些结构退化时释放的脂质的局部运输和再利用。
Apolipoprotein-E (apoE) is a constituent of various lipoproteins and is a ligand for cellular lipoprotein receptors. Unlike most apolipoproteins, apoE is synthesized in peripheral tissues, including those engaged in steroidogenesis. ApoE expression in adrenal cells inhibits cholesterol utilization for steroid synthesis and blocks signal transduction via the protein kinase-A pathway. In cultured ovarian thecal/interstitial cells, exogenous apoE has been shown to inhibit LH-induced androgen synthesis. These findings support a role for apoE as an autocrine or paracrine factor involved in regulating steroidogenesis. In the present study in situ hybridization was used to identify cell types that express apoE mRNA in ovaries from rats with a 4-day estrous cycle, from pregnant rats, from immature rats treated with PMSG to stimulate follicular development, and from PMSG-treated rats that were subsequently administered hCG to stimulate ovulation and luteinization. ApoE mRNA was localized to theca and interstitial cells of follicles in animals at all stages of the estrous cycle as well as in immature rats treated with PMSG. ApoE mRNA was not detected in oocytes, cumulus cells, or granulosa cells. High levels of apoE mRNA also were expressed by localized clusters of presumptive macrophages in atretic follicles and degenerating corpora lutea. This complex pattern of expression may indicate that apoE has multiple functions in the rat ovary. ApoE made by theca and interstitial cells may act locally as an autocrine factor to regulate androgen production. ApoE made in atretic follicles and regressing corpora lutea may serve to facilitate local transport and reutilization of lipid released as these structures degenerate.