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标题：Gene transcription of the retinoid X receptor α (RXRα) is regulated by fatty acids and hormones in rat hepatic cells
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作者：Hilde Hermansen Steineger ; Borghild M. Arntsen ; Øystein Spydevold 等
期刊名称：JLR Papers In Press
印刷版ISSN：0022-2275
电子版ISSN：1539-7262
出版年度：1998
卷号：39
期号：4
页码：744-754
语种：English
出版社：American Society for Biochemistry and Molecular Biology
摘要：This work describes the molecular mechanisms of fatty acid and hormonal modulations of the retinoid X receptor α (RXRα) in rat liver cells. We examined the effects of different fatty acids (myristic, stearic, oleic, linolenic, and arachidonic acids, EPA, and the peroxisomal proliferator TTA) and several hormones (the glucocorticoid analogue dexamethasone, insulin, and retinoic acid) on the RXRα mRNA and protein levels in rat hepatoma cells and cultured hepatocytes. The fatty acids induced the RXRα gene expression resulting in up to 3-fold induction. Dexamethasone alone induced the mRNA level and, in combination with fatty acids, an additive or synergistic effect was observed. The dexamethasone-increased mRNA level was obliterated by insulin. The same pattern of regulation of the protein level was observed when determined in cultured hepatocytes, but the induced protein level showed a lower magnitude of stimulation than the mRNA level. This could indicate a post-transcriptional modulation of the RXRα gene expression. Time course studies showed a maximal induction of mRNA and protein levels after 18 h and 48 h, respectively. Our results uniformly show that the RXRα gene expression is under distinct regulation by fatty acids and hormones which suggests a coupling with the lipid metabolizing system and the hormonal signaling pathway. —Steineger, H. H., B. M. Arntsen, Ø. Spydevold, and H. N. Sørensen. Gene transcription of the retinoid X receptor α (RXRα) is regulated by fatty acids and hormones in rat hepatic cells. J. Lipid Res. 1998. 39: 744–754.
关键词：dexamethasone ; insulin ; mRNA level ; protein level ; regulation