title: Effects of catechin-rich green tea on gene expression of gluconeogenic enzymes in rat hepatoma H4IIE cells.
abstract: Rat hepatoma H4IIE cells were stimulated with dexamethasone and dibutyryl cAMP to increase gene expressions of gluconeogenic enzymes, glucose-6-phosphatase (G6Pase) and phosphoenolpyruvate carboxykinase (PEPCK). Inclusion of catechin-rich green tea beverage (GTB) in the culture medium reduced the up-regulation of these genes as well as that of hepatocyte nuclear factor 4 alpha (HNF4alpha) gene. GTB was fractionated into chloroform-soluble (Fraction I), ethyl acetatesoluble (Fraction II), methanol-soluble (Fraction III) and residual (Fraction IV) fractions. Fractions II and III containing catechins caused an attenuation of the up-regulated expression of these genes as well as the down-regulation of HNF4alpha gene expression. Fraction IV had a synergistic effect on the up-regulation by dexamethasone/dibutyryl cAMP of the PEPCK gene expression and upregulated HNF4alpha gene expression. These results suggest that GTB down-regulated the expression of the HNF4alpha gene to cause the down-regulated gene expression of gluconeogenic enzymes. One reason why GTB did not down-regulate hepatic PEPCK gene expression in previous animal experiments may be that the component(s) acting to up-regulate PEPCK gene expression was more effective in vivo than in cultured cells.
authors.affiliation: Health Care Research Center, Nisshin Pharma Inc., Fujimino, Saitama 356-8511, Japan.
authors.forename: Kensuke
authors.initials: K
authors.lastname: Yasui
authors.forename: Hiroki
authors.initials: H
authors.lastname: Tanabe
authors.forename: Norihisa
authors.initials: N
authors.lastname: Okada
authors.forename: Ryuuta
authors.initials: R
authors.lastname: Fukutomi
authors.forename: Yoko
authors.initials: Y
authors.lastname: Ishigami
authors.forename: Mamoru
authors.initials: M
authors.lastname: Isemura
mesh_terms: D000818:Animals; D001483:Base Sequence; D002392:Catechin / Q000494:pharmacology*; D045744:Cell Line, Tumor; D017931:DNA Primers; D005786:Gene Expression Regulation / Q000187:drug effects*; D005943:Gluconeogenesis / Q000235:genetics*; D005952:Glucose-6-Phosphatase / Q000235:genetics*; D007328:Insulin / Q000494:pharmacology; D008114:Liver Neoplasms, Experimental / Q000201:enzymology* / Q000235:genetics; D019764:Phosphoenolpyruvate Carboxykinase (ATP) / Q000235:genetics*; D016133:Polymerase Chain Reaction; D051381:Rats; D013662:Tea / Q000737:chemistry*
chemical_list: D017931:DNA Primers; D007328:Insulin; D013662:Tea; D002392:Catechin; D005952:Glucose-6-Phosphatase; D019764:Phosphoenolpyruvate Carboxykinase (ATP)