Cytochrome P450 1A (CYP 1A) is a member of a multigene family of xenobiotic metabolizing enzymes. CYP 1A is highly inducible by numerous environmental contaminants including polycyclic aromatic hydrocarbons (PAHs) and is widely used in biomonitoring studies. Therefore, understanding the regulation of this gene is important for accurate interpretation of biomarker data. We describe here the func...

To investigate the auto-induction of cytochrome P450 (CYP450) by Chloroxoquinoline (CXL), a novel anticancer drug. Three experiments related to the induction of CYP450 were performed: a) In vitro use of the rat fresh hepatocytes model; b) In vivo 'cocktail' of CYP450 probe model; c) Pharmacokinetic (PK) study of the single and multiple doses. Some typical CYP enzyme probes and inducers were use...

The effects of three selective oral inhibitors, fluvoxamine (FLU), ketoconazole (KET), and verapamil (VER), on the pharmacokinetics (PK) of florfenicol (FFC) were investigated in chickens. The chickens were administered orally with saline solution (SAL), FLU (60 mg/kg), KET (25 mg/kg), or VER (9 mg/kg) for 7 consecutive days. Florfenicol was given to the chickens at a single dose of 30 mg/kg or...

The inhibitory effect of six newly synthesized ethnyl-derivatives on the activity of cytochrome P450 isoenzymes were investigated in rat liver microsomes. 6 μM concentration of each compound against different concentrations of the substrates (1, 2, 4, 8 and 16 μM) was used: 7-ethoxy resorufin "EROD" in β-Naphthoflavone "β-NF"induced CYP 1A isoenzyme and 7-pentoxy resorufin "PROD" in phenobarbit...

To investigate the hypothesis that tumor promotion by chlorinated aromatic hydrocarbons involves Ah receptor occupation and subsequent induction of cytochromes P-450 1a-1, effects of Aroclor 1254 or 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) were examined in N-nitrosodiethylamine-initiated mice with different Ah receptor phenotype. Levels of cytochromes P-450 1a and 2b were measured by enzyme a...

The isolated perfused rat mesenteric bed releases endothelium-derived hyperpolarizing factor (EDHF) in response to acetylcholine (ACh) or histamine. I propose that EDHF released in the mesenteric vascular bed is a cytochrome P450 (CYP)-linked, arachidonate metabolite. In the presence of nitro-L-arginine methyl ester (L-NAME) and indomethacin, injections of ACh (0.001 to 10 nmol) or histamine (0...

The increasing needs of personalized therapies have recently stimulated impressive advances in research and development of portable point-of-care biosensors for realtime monitoring as well as biosensors for drug development [1, 2]. Enzymatic amperometric biosensors based on the enzyme family cytochrome P450 (CYP) have drawn increasing attention because CYP is a monooxygenase enzyme primarily in...

3-Amino-1,4-dimethyl-5H-pyrido[4,3-b]indole (Trp-P-1) is known as a dietary carcinogen and it requires metabolic activation by cytochrome P450 (CYP) 1A subfamily to have carcinogenicity. On the other hand, our previous report demonstrated that Trp-P-1 induces apoptosis in primary cultured rat hepatocytes, but the metabolically activated Trp-P-1 added extracelluarly to hepatocytes did not induce...

Objective Indiscriminate use of synthetic pyrethroid insecticides, Cypermethrin (Cyp) and Deltamethrin (Del) have been reported to cause system toxicity in mammals including humans. The dietary antioxidants protects tissues and organs against insecticides/xenobiotic induced damage. In present study, we evaluated the effect of exposure of Cyp and Del and possible protective roles of curcumin and...

Mifepristone (RU486), an 11beta-substituted nor-steroid containing a 17alpha-1-propynyl group used clinically as an antiprogestin agent for medical abortions, was demonstrated to be a selective mechanism-based inactivator of human cytochrome P-450-3A4 (CYP-3A4). The loss of testosterone 6beta-hydroxylation activity was time- and concentration-dependent as well as requiring metabolism of mifepri...