We investigated gender-related differences in the ability of selected flavonoids and phenolic compounds to modify porcine hepatic CYP450-dependent activity. Using pools of microsomes from male and female pigs, the inhibition of the CYP families 1A, 2A, 2E1, and 3A was determined. The specific CYP activities were measured in the presence of the following selected compounds: rutin, myricetin, quercetin, isorhamnetin, p-coumaric acid, gallic acid, and caffeic acid. We determined that myricetin and isorhamnetin competitively inhibited porcine CYP1A activity in the microsomes from both male and female pigs but did not affect the CYP2A and CYP2E1. Additionally, isorhamnetin competitively inhibited CYP3A in both genders. Noncompetitive inhibition of CYP3A activity by myricetin was observed only in the microsomes from male pigs, whereas CYP3A in female pigs was not affected. Quercetin competitively inhibited CYP2E1 and CYP1A activity in the microsomes from male pigs and irreversibly CY3A in female pigs. No effect of quercetin on CYP2E1 was observed in the microsomes from female pigs. Neither phenolic acids nor rutin affected CYP450 activities. Taken together, our results suggest that the flavonoids myricetin, isorhamnetin, and quercetin may affect the activities of porcine CYP1A, CYP3A, and CYP2E1 in a gender-dependent manner.

• MeSH
• inhibitory cytochromu P450 farmakologie   MeSH
• jaterní mikrozomy enzymologie   MeSH
• pohlavní dimorfismus * MeSH
• prasata MeSH
• systém (enzymů) cytochromů P-450 metabolismus   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• inhibitory cytochromu P450 MeSH
• systém (enzymů) cytochromů P-450 MeSH

Cytochrome P450 (CYP) is a heme protein oxidizing various xenobiotics, as well as endogenous substrates. Understanding which CYP enzymes are involved in metabolic activation and/or detoxication of different compounds is important in the assessment of an individual's susceptibility to the toxic action of these substances. Therefore, investigation which of several in vitro experimental models are appropriate to mimic metabolism of xenobiotics in organisms is the major challenge for research of many laboratories. The aim of this study was to evaluate the efficiency of different in vitro systems containing individual enzymes of the mixed-function monooxygenase system to oxidize two model substrates of CYP3A enzymes, exogenous and endogenous compounds, α-naphtoflavone (α-NF) and testosterone, respectively. Several different enzymatic systems containing CYP3A enzymes were utilized in the study: (i) human hepatic microsomes rich in CYP3A4, (ii) hepatic microsomes of rabbits treated with a CYP3A6 inducer, rifampicine, (iii) microsomes of Baculovirus transfected insect cells containing recombinant human CYP3A4 and NADPH:CYP reductase with or without cytochrome b(5) (Supersomes™), (iv) membranes isolated from of Escherichia coli, containing recombinant human CYP3A4 and cytochrome b(5), and (v) purified human CYP3A4 or rabbit CYP3A6 reconstituted with NADPH:CYP reductase with or without cytochrome b(5) in liposomes. The most efficient systems oxidizing both compounds were Supersomes™ containing human CYP3A4 and cytochrome b(5). The results presented in this study demonstrate the suitability of the supersomal CYP3A4 systems for studies investigating oxidation of testosterone and α-NF in vitro.

• Klíčová slova
• cytochrome P450 3A, metabolism, α-naphthoflavone,
• Publikační typ
• časopisecké články MeSH