Possible Involvement of Chlorinated Ethylenes in Arylhydrocarbon Receptor-Related Induction of Cytochrome P4501A1 (CYP1A1) in Human Hepatoma HepG2 Cells

Induction of cytochrome P4501A1.

Cytochrome P4501A1 is a substrate-inducible microsomal enzyme that oxygenates polycyclic aromatic hydrocarbons, such as the carcinogen benzo(a)pyrene, as the initial step in their metabolic processing to water-soluble derivatives. Enzyme induction reflects increased transcription of the cognate CYP1A1 gene. The environmental toxicant 2,3,7,8-tetrachlorodibenzo-p-dioxin is the most potent known ...

Persistent induction of cytochrome P4501A1 in human hepatoma cells by 3-methylcholanthrene: evidence for sustained transcriptional activation of the CYP1A1 promoter.

Cytochrome P450 (P450)1A1 plays a critical role in the metabolic activation and detoxification of polycyclic aromatic hydrocarbons (PAHs), many of which are potent human carcinogens. In this investigation, we tested the hypothesis that MC elicits persistent induction of CYP1A1 expression in human hepatoma cells (HepG2) and that this phenomenon is mediated by sustained transcriptional activation...

Jpet # 162222 1 Persistent Induction of Cytochrome P4501a1 in Human Hepatoma Cells by 3-methylcholanthrene: Evidence for Sustained Transcriptional Activation of the Cyp1a1 Promoter

POSSIBLE INVOLVEMENT OF GABAA RECEPTOR SITES IN CATALEPSY

The present work was performed to show the possible interaction of GAB A, and GABAB receptors in catalepsy. The following results were obtained: 1- Muscimol (MUS), a GABAA agonist, induced catalepsy. This effect was dose-dependent. Baclofen (BAC), a GABAB agonist, had no effect in this respect. 2- Catalepsy induced by muscimol was potentiated by pretreatment of animals with bicuculline (BI...

Estrogen receptor reduces CYP1A1 induction in cultured human endometrial cells.

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) exerts its toxic action via the aryl hydrocarbon (Ah) receptor, which induces a battery of xenobiotic-metabolizing enzymes, including the cytochrome P450 isozyme, CYP1A1. TCDD-induced 7-ethoxycoumarin-O-deethylase activity was reduced 75% in cultured human endometrial ECC-1 cells exposed to various concentrations of 17beta-estradiol for up to 72 h, wit...