Comparison of three fluorescent CYP3A substrates in two vertebrate models: pig and Atlantic salmon

Žlábek, Vladimír; Zamaratskaia, Galia

doi:10.1017/s1751731111002096

Cited by 33 publications

(10 citation statements)

References 35 publications

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“…These inhibitors have previously been shown to have an effect on the activities of CYP450 isoforms in microsomal or hepatocyte assays Rasmussen et al, 2011b;Zlabek and Zamaratskaia, 2012). The incubations were performed in the presence of 0.125, 1.25 and 12.5 µM of the specific inhibitor, except for E2 (used concentration 0.002, 0.02 and 0.2 µM) and quercetin (16, 32 and 128 µM).…”

Section: Microsomal Incubations With Cyp450 Isoform Inhibitorsmentioning

confidence: 99%

Gender-related differences in the formation of skatole metabolites by specific CYP450 in porcine hepatic S9 fractions

Borrisser-Pairó¹,

Rasmussen

Ekstrand

et al. 2015

Animal

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Higher accumulation of skatole in the fat of male pigs compared with female pigs might be due to gender-related differences in the rate of skatole degradation. In the present study, skatole metabolites and cytochrome P450 (CYP450) isoforms involved in skatole metabolism were for the first time investigated in hepatic S9 fractions from six male and four female pigs (crossbred Landrace × Yorkshire dams and Duroc boar). Surprisingly, the rates of production of major skatole metabolites were similar in male and female pigs. The most abundant metabolite of skatole was 3-hydroxy-3-methyloxindole (HMOI) followed by 3-methyloxindole and indole-3-carbinol in both male and female S9 fractions. Concentrations of formed HMOI and 3-methyloxindole did not differ between the genders (P = 0.124 for HMOI, and P = 0.575 for 3-methyloxindole). Indole-3-carbinol formation was higher in S9 fractions from the females compared with male pigs (P = 0.0001). Enzyme kinetic parameters were similar for both genders (P > 0.05). In both male and female pigs, ellipticine, diallyl sulphide (DAS) and quercetin inhibited HMOI formation, confirming the involvement of CYP1A1 and CYP2E1. The formation of 3-methyloxindole was reduced in the presence of the CYP2E1 inhibitor DAS, and formation of indole-3-carbinol was reduced in the presence of CYP1A1 and CYP2A19 inhibitors. We found only minor differences in skatole metabolism between male and female pigs, particularly the involvement of CYP2C and CYP3A in indole-3-carbinol formation in female but not in male pigs. This is a very essential finding, suggesting the involvement of larger number of CYP450 isoforms in female pigs. On the other hand, indole-3-carbinol is a minor skatole metabolite, and the physiological significance of CYP2C and CYP3A involvement in its formation in female pigs, but not in male pigs, needs to be elucidated. Our results, however, should be interpreted with caution because of the low number of animals and possibility of breed and age effects on skatole metabolism.Keywords: boar taint, skatole, 3-methyloxindole, indole-3-carbinol, 3-hydroxy-3-methyloxindole, CYP450 isoforms ImplicationsWe studied skatole metabolism in hepatic S9 fractions from male and female pigs. Generally, skatole levels are higher in entire male than in female pigs. Until recently, we believed that this is because of the differences in skatole metabolism between male and female pigs. The present study suggests that production of skatole metabolites is similar in both male and female pigs. We found only minor differences in skatole metabolism, particularly the involvement of CYP2C and CYP3A in indole-3-carbinol formation. These results contribute to the knowledge on skatole metabolism by CYP450 and are of interest for animal and meat scientists.

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Section: Microsomal Incubations With Cyp450 Isoform Inhibitorsmentioning

confidence: 99%

Gender-related differences in the formation of skatole metabolites by specific CYP450 in porcine hepatic S9 fractions

Borrisser-Pairó¹,

Rasmussen

Ekstrand

et al. 2015

Animal

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“…Both BROD and BFCOD are considered to be marker reactions to estimate the CYP3A activity. Our previous study showed that these reactions were strongly inhibited by ketoconazole, a well‐known inhibitor of CYP3A (Zlabek and Zamaratskaia 2011). Interestingly, these reactions showed differences in response to testicular steroids.…”

Section: Discussionmentioning

confidence: 99%

“…The activities of CYP3A were estimated as activities of BR O-dealkylase (BROD) and BFC O-debenzylase (BFCOD) (Zlabek and Zamaratskaia 2011). CYP2C activity was estimated using two substrates, tolbutamide and diclofenac.…”

Section: Preparation Of Hepatic Microsomes and Enzymatic Activitymentioning

confidence: 99%

In vitro and In vivo Association of Porcine Hepatic Cytochrome P450 3A and 2C Activities with Testicular Steroids

Zamaratskaia

Žlábek

Ropstad

et al. 2012

Reprod Domestic Animals

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The aim of this study was to screen the inhibitory potential of several testicular steroids on cytochrome P450 3A (CYP3A) and 2C (CYP2C) activities in porcine liver microsomes. The microsomes used in this study were obtained from pubertal male pigs of two breeds, Landrace and Duroc. For the in vitro inhibition study, porcine microsomes were incubated in the presence of 17β-estradiol, 17α-estradiol, androstenone, dehydroepiandrosterone and dihydrotestosterone. Both reversible and mechanism-based inhibitions were examined. 7-benzyloxyresorufin (BR) and 7-benzyloxy-4-trifluoromethylcoumarin (BFC) were used as substrates for CYP3A, and diclofenac and tolbutamide (TB) as substrates for CYP2C. 7-benzyloxyresorufin O-dealkylase (BROD) activity was inhibited by all tested steroids in the microsomes from Landrace pigs via mechanism-based mode, but in the microsomes from Duroc pigs, BROD activities were inhibited only in the presence of 17β-oestradiol. Mechanism-based inhibition of BFC metabolism by the tested steroids was observed in the microsomes from both breeds, but this inhibition was weak and did not exceed 20%. TB hydroxylase (TBOH) activity in the microsomes from Duroc pigs was inhibited by 17α-oestradiol through the mechanism-based mode of inhibition. None of the investigated steroids inhibited TBOH activity in Landrace pigs. For the in vivo study, male pigs were injected with a single dose of human chorionic gonadotropin (hCG) to stimulate testicular steroid production by the Leydig cells. In vivo stimulation with hGC did not alter BROD activity either in Landrace or in Duroc pigs. BFC metabolism was significantly induced by hCG stimulation in both breeds and TBOH activity only in Duroc pigs. Activity of diclofenac hydroxylase was not detected in either Landrace or Duroc pigs. Breed significantly affected BROD and TBOH activity with BROD being higher in Landrace and TBOH in Duroc pigs. This study improved our understanding of the role of testicular steroids in the regulation of porcine CYP450 activity.

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“…The effect of ketoconazole on xenobiotic metabolism is multifaceted. Ketoconazole can modulate mRNA, protein expression and catalytic activities of several fishCYP450 isoforms (Hasselberg et al, 2005;Hegelund et al, 2004;Zlabek and Zamaratskaia, 2012). Clotrimazole was also shown to affect PXR (Moore et al, 2002) and AhR (Navas et al, 2004a).…”

Section: Azolesmentioning

confidence: 99%

“…Clotrimazole was also shown to affect PXR (Moore et al, 2002) and AhR (Navas et al, 2004a). A note of caution should be introduced becausein vitro studies demonstrated inhibition of CYP1A and CYP3A by clotrimazole (Burkina et al, 2013) and by ketoconazole (Hegelund et al, 2004;Zlabek and Zamaratskaia, 2012). It is evident that although the activities of CYP1A and CYP3A are regulated via AhR and PXR, they can also be directly controlled by non-receptor mediated mechanisms.…”

Section: Azolesmentioning

confidence: 99%

Effects of pharmaceuticals present in aquatic environment on Phase I metabolism in fish

Burkina

Žlábek

Zamaratskaia

2015

Environmental Toxicology and Pharmacology

122

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Comparison of three fluorescent CYP3A substrates in two vertebrate models: pig and Atlantic salmon

Cited by 33 publications

References 35 publications

Gender-related differences in the formation of skatole metabolites by specific CYP450 in porcine hepatic S9 fractions

Gender-related differences in the formation of skatole metabolites by specific CYP450 in porcine hepatic S9 fractions

In vitro and In vivo Association of Porcine Hepatic Cytochrome P450 3A and 2C Activities with Testicular Steroids

Effects of pharmaceuticals present in aquatic environment on Phase I metabolism in fish

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