Regulation of cytochrome P4501A1 expression by steroid compounds스테로이드 화합물에 의한 cytochrome P4501A1 발현의 조절에 관한 연구

Cited 0 time in webofscience Cited 0 time in scopus
  • Hit : 379
  • Download : 0
Cytochrome P4501A1 inducibility of estradiol and progesterone was investigated in mouse hepatoma Hepa 1c1c7 cells. Estradiol and progesterone increased cytochrome P4501A1-specific 7-ethoxyresorufin O-deethylase (EROD) activity at the concentrations higher than 1μM. This induction was dose- and time-related. At low concentrations less than 1μM, neither estradiol nor progesterone had EROD inducibility. To determine the possible involvement of steroid hormone receptors in the induction hormone receptor antagonists were treated together with steroids. Tamoxifen, an antagonist for estrogen receptor, could not recover the action of estradiol and RU486, an antagonist for progesterone receptor, also could not alleviate the action of progesterone. These results indicated that the EROD induction by estradiol and progesterone was independent of their cognate sex hormone receptors. In order to investigate the mechanism responsible for the EROD induction, immunoblot and northern blot analysis were performed. The increase in EROD activity by sex steroids was due to the increase in the amounts of corresponding cytochrome P4501A1 protein and CYP1A1 mRNA. Therefore, it was speculated that the CYP1A1 induction by sex steroids was dependent on transcriptional of CYP1A1 gene. Transient transfection assay using CYP1A1-CAT reporter plasmid containing 5``-upstream regulatory region of CYP1A1 gene showed that the inserted 482 bp fragment had sufficient regulatory sequences necessary for the CYP1A1 induction by sex steroids. To identify the minimal sequences responsible for the induction, electrophoretic mobility shift assay was performed with the oligonucleotide of dioxin responsive element (DRE), which has been known to be most important in up-regulation of CYP1A1 expression. Estradiol and progesterone stimulated the formation of DRE-aromatic hydrocarbon receptor (AhR) complexes in Hepa 1c1c7 cell cultures. AhR was shown to be directly activated by binding of estradiol and progester...
Yang, Kyu-Hwan양규환
한국과학기술원 : 생물과학과,
Issue Date
144184/325007 / 000935252

학위논문(박사) - 한국과학기술원 : 생물과학과, 1998.8, [ ix, 120 p. ]

Appears in Collection
Files in This Item
There are no files associated with this item.


  • mendeley


rss_1.0 rss_2.0 atom_1.0