title: Regulation of retinoid X receptor gamma expression by fed state in mouse liver.
abstract: Glucose metabolism is balanced by glycolysis and gluconeogenesis with precise control in the liver. The expression of genes related to glucose metabolism is regulated primarily by glucose and insulin at transcriptional level. Nuclear receptors play important roles in regulating the gene expression of glucose metabolism at transcriptional level. Some of these nuclear receptors form heterodimers with RXRs to bind to their specific regulatory elements on the target promoters. To date, three isotypes of RXRs have been identified; RXRα, RXRβ and RXRγ. However, their involvement in the interactions with other nuclear receptors in the liver remains unclear. In this study, we found RXRγ is rapidly induced after feeding in the mouse liver, indicating a potential role of RXRγ in controlling glucose or lipid metabolism in the fasting-feeding cycle. In addition, RXRγ expression was upregulated by glucose in primary hepatocytes. This implies that glucose metabolism governed by RXRγ in conjunction with other nuclear receptors. The luciferase reporter assay showed that RXRγ as well as RXRα increased SREBP-1c promoter activity in hepatocytes. These results suggest that RXRγ may play an important role in tight control of glucose metabolism in the fasting-feeding cycle.
authors: Department of Biochemistry, College of Medicine, Catholic Kwandong University, Gangneung 210-701, Republic of Korea. Electronic address: 49park@cku.ac.kr.
authors: Sangkyu
authors: S
authors: Park
authors: Division of Metabolic Disease, Center for Biomedical Sciences, National Institute of Health Korea, Osong 361-709, Republic of Korea.
authors: Yoo Jeong
authors: YJ
authors: Lee
authors: Department of Biochemistry and Molecular Biology, Integrated Genomic Research Center for Metabolic Regulation, Institute of Genetic Science, Yonsei University College of Medicine, Seoul 120-752, Republic of Korea.
authors: Eun Hee
authors: EH
authors: Ko
authors: Department of Biochemistry and Molecular Biology, Integrated Genomic Research Center for Metabolic Regulation, Institute of Genetic Science, Yonsei University College of Medicine, Seoul 120-752, Republic of Korea; Brain Korea 21 PLUS Project for Medical Science, Yonsei University, Seoul 120-752, Republic of Korea.
authors: Jae-Woo
authors: JW
authors: Kim
mesh_terms: D000818:Animals; D004435:Eating / Q000502:physiology*; D005215:Fasting / Q000378:metabolism; D005947:Glucose / Q000378:metabolism* / Q000494:pharmacology; D022781:Hepatocytes / Q000187:drug effects / Q000378:metabolism; D008099:Liver / Q000378:metabolism*; D000071518:Liver X Receptors; D008297:Male; D008810:Mice, Inbred C57BL; D057093:Orphan Nuclear Receptors / Q000378:metabolism; D011401:Promoter Regions, Genetic; D020218:Response Elements; D047491:Retinoid X Receptor gamma / Q000235:genetics / Q000378:metabolism*; D051780:Sterol Regulatory Element Binding Protein 1 / Q000235:genetics / Q000378:metabolism
chemical_list: D000071518:Liver X Receptors; D057093:Orphan Nuclear Receptors; D047491:Retinoid X Receptor gamma; C497388:Srebf1 protein, mouse; D051780:Sterol Regulatory Element Binding Protein 1; D005947:Glucose
keywords: Feeding; Glucose; Lipid metabolism; Liver; RXRγ