• 한국산업보건학회지
• /
• 제19권1호
• /
• pp.73-79
• /
• 2009

This study was undertaken to investigate the effects of single and combined exposure of toluene (T) and xylene (X) on the cytochrome-450(CYP)-mediated metabolizing capacity, induction of CYP isozymes and the excretion of their metabolites in urine. Animal were adults male Sprague-Dawley (SD) rats and divided into 4 groups such as control, T (treated with 63.7 mg/body kg), X (treated with 65.9 mg/body kg) and TX(T=X). Organic solvents was administrated by intraperitoneal injection for 3 days. The contents of protein and CYP in liver microsomes of control group were $16.48{\pm}0.56 mg/m{\ell}$ and $0.744{\pm}0.025$ nmol/mg protein, respectively, and they contents were significantly lower than in derived from treated groups (p<0.01). The activities of PROD and ${\rho}NPH$ were significantly higher in single treated groups than in control and combined group (TX). When Western immunoblotting were carried out with two monoclonal antibodies (MAb 1-98-1 and MAb 2-66-3) which were specific against CYP2B1/2 and CYP2E1, respectively, a strong signal corresponding to CYP2B1/2 was observed in microsomes obtained from rats treated with X and TX. The color density against CYP2E1 was slightly increased in T and TX groups compared with C and X groups. The amounts of urinary hippuric acid in T single treated group was $3.29{\pm}1.97$ g/g creatinine and TX combined group was $2.91{\pm}1.76$ g/g creatinine, but was not significant. However, amount of urinary methy hippuric acid in X single treated group ($1.62{\pm}0.72$ g/g creatinine) was significantly higher than TX combined group ($0.93{\pm} 0.63$ g/g creatinine)(p<0.01). These results suggested that CYP2E1 isozyme might be responsible for the metabolism of T, and CYP2B1/2 isozyme is for X. And also, difference of metabolites level between single and combined group may be speculated that the intermediates of T and X interacted each other in the process of their metabolite formation reaction.

• Biomolecules & Therapeutics
• /
• 제23권5호
• /
• pp.486-492
• /
• 2015

Drug metabolism mostly occurs in the liver. Cytochrome P450 (CYP) is a drug-metabolizing enzyme that is responsible for many important drug metabolism reactions. Recently, the US FDA and EU EMA have suggested that CYP enzyme induction can be measured by both enzymatic activity and mRNA expression. However, these experiments are time-consuming and their interassay variability can lead to misinterpretations of the results. To resolve these problems and establish a more powerful method to measure CYP induction, we determined CYP induction by using luminescent assay. Luminescent CYP assays link CYP enzyme activity to firefly luciferase luminescence technology. In this study, we measured the induction of CYP isozymes (1A2, 2B6, 2C9, and 3A4) in cryopreserved human hepatocytes (HMC424, 478, and 493) using a luminometer. We then examined the potential induction abilities (unknown so far) of mesalazine, a drug for colitis, and mosapride citrate, which is used as an antispasmodic drug. The results showed that mesalazine promotes CYP2B6 and 3A4 activities, while mosapride citrate promotes CYP1A2, 2B6, and 3A4 activities. Luminescent CYP assays offer rapid and safe advantages over LC-MS/MS and qRT-PCR methods. Furthermore, luminescent CYP assays decrease the interference between the optical properties of the test compound and the CYP substrates. Therefore, luminescent CYP assays are less labor intensive, rapid, and can be used as robust tools for high-throughput CYP screening during early drug discovery.

• Preventive Nutrition and Food Science
• /
• 제6권1호
• /
• pp.57-61
• /
• 2001

Conjugated linoleic acid (CLA), when incorporated into mouse liver microsomal membranes, selectively inhibits the mutagenesis of 2-amino-3-methylimidazo[4,5-f] quinoline (IQ). Nine-week old female ICR mice were given (p.o.) 0.1 mL olive oil alone (control), 0.1 mL olive oil plus 0.1 mL linoleic acid, or 0.1 mL olive oil plus 0.1 mL CLA, twice weekly for four weeks. The animals were then sacrificed and liver S-9 fractions were prepared. Activation of IQ for mutagenesis by the liver S-9 from CLA-treated mice was significantly reduced in comparison wit liver S-9 from control or linolic acid-treated mice. By contrast, the activation of 7,12-dimethylbenz[a] anthracene (DMBA) and benzo[a] pyrene (BP) was unaffected. Hence, CLA incorporated into phospholipids may selectively affect cytochrome P450 isozymes responsible for activating IQ, but not those which activate BP or DMBA. The addition of free CLA or the methyl esters of CLA, linoleic acid, or oleic acid, to control S-9 inhibited the activation of all three mutagens (IQ, BP, and DMBA).