title: Down-regulation of immediate early gene egr-1 expression in rat C6 glioma cells by short-term exposure to high salt culture medium.
abstract: Influence of high salt culture conditions on the expression of immediate early gene egr-1 in rat C6 glioma cells was investigated by measuring both Egr-1 mRNA and protein levels in the cells exposed to the medium containing high concentrations of NaCl. The exposure to high salt medium reduced Egr-1 mRNA and protein levels, while Egr-1 mRNA levels were not altered by the medium containing either sucrose or glycerol. Veratridine and monensin also reduced Egr-1 mRNA levels, similar in extent to that induced by high salt medium. Imaging analysis indicated that the exposure to high salt medium induced the elevation of Na+ levels within the cells. These results indicate that neither hyperosmotic pressure nor ionic strength of high salt medium contribute to the reduction of Egr-1 expression, and suggest that the elevation of intracellular Na+ concentration is closely associated with the down-regulation of egr-1 gene expression.
authors.affiliation: Department of Pharmacology, Tokushima University School of Medicine, 3-18-15 Kuramoto, Tokushima 770-8503, Japan. km@basic.med.tokushima-u.ac.jp
authors.forename: Kyoji
authors.initials: K
authors.lastname: Morita
authors.forename: Hideki
authors.initials: H
authors.lastname: Arimochi
authors.forename: Shigeru
authors.initials: S
authors.lastname: Yoshida
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism; D045744:Cell Line, Tumor; D003470:Culture Media; D004268:DNA-Binding Proteins / Q000096:biosynthesis*; D015536:Down-Regulation; D051766:Early Growth Response Protein 1; D005786:Gene Expression Regulation / Q000187:drug effects; D017781:Genes, Immediate-Early; D005910:Glioma; D017874:Immediate-Early Proteins / Q000096:biosynthesis*; D008985:Monensin / Q000494:pharmacology; D009994:Osmolar Concentration; D051381:Rats; D012462:Saline Solution, Hypertonic / Q000494:pharmacology*; D012964:Sodium / Q000378:metabolism; D014157:Transcription Factors / Q000096:biosynthesis*; D014701:Veratridine / Q000494:pharmacology
chemical_list: D003470:Culture Media; D004268:DNA-Binding Proteins; D051766:Early Growth Response Protein 1; C486110:Egr1 protein, rat; D017874:Immediate-Early Proteins; D012462:Saline Solution, Hypertonic; D014157:Transcription Factors; D014701:Veratridine; D008985:Monensin; D012964:Sodium; D002118:Calcium