Ginsenoside Rg1 down-regulates glucocorticoid receptor and displays synergistic effects with cAMP.
Ginsenoside-Rg1 (G-Rg1) from the roots of Panax ginseng C. A. Meyer has been shown to bind to the glucocorticoid receptor (GR). To further explore the effect of G-Rg1 binding to GR, a luciferase reporter gene containing two copies of a glucocorticoid response element was constructed and transiently transfected into FTO2B rat hepatoma cells. A dose-dependent induction of the reporter gene was observed in response to G-Rg1, and the inductive effect was blocked by treatment with the antiglucocorticoid RU486. In addition, both G-Rg1- and dexamethasone (Dex)-induced transcription was synergistically enhanced by the treatment of dibutyryl cAMP (Bt2-cAMP). G-Rg1 treatment also led to the down-regulation of intracellular GR content, which was similar to the effect of Dex. By showing that G-Rg1 down-regulates GR and induces GR-mediated transcription synergistically with cAMP, we conclude that G-Rg1 is a functional GR ligand in FTO2B cells.
Chung
E
E
College of Pharmacy, Seoul National University, Korea.
Lee
K Y
KY
Lee
Y J
YJ
Lee
Y H
YH
Lee
S K
SK
D000818:Animals; D006528:Carcinoma, Hepatocellular; D000242:Cyclic AMP / Q000494:pharmacology*; D003907:Dexamethasone / Q000494:pharmacology; D015536:Down-Regulation / Q000187:drug effects* / Q000235:genetics; D004357:Drug Synergism; D004365:Drugs, Chinese Herbal / Q000494:pharmacology*; D005786:Gene Expression Regulation / Q000187:drug effects; D017930:Genes, Reporter / Q000187:drug effects; D036145:Ginsenosides; D051381:Rats; D011965:Receptors, Glucocorticoid / Q000096:biosynthesis / Q000187:drug effects* / Q000235:genetics; D012503:Saponins / Q000494:pharmacology*; D014407:Tumor Cells, Cultured
D004365:Drugs, Chinese Herbal; D036145:Ginsenosides; D011965:Receptors, Glucocorticoid; D012503:Saponins; D003907:Dexamethasone; D000242:Cyclic AMP; C035054:ginsenoside Rg1