In vitro inhibition of porcine cytochrome P450 by 17β-estradiol and 17α-estradiol

Zamaratskaia, Galia; Rasmussen, Martin; Herbin, Isabelle; Ekstrand, Bo; Zlabek, Vladimir

doi:10.2478/v10102-011-0014-x

Abstract

Sexually mature pigs are known to possess high concentrations of testicular steroids, which have been shown to change the activities of cytochrome P450 in vitro. The aim of the present study was to evaluate the regulation of CYP1A and CYP2E1 activity by the steroids dihydrotestosterone (DHT), 3β-androstenol, 17β-estradiol and 17α-estradiol. Catalytic activities of 7-ethoxyresorufin O-deethylase (EROD) and 7-methoxyresorufin O-demethylase (MROD) were used as markers of CYP1A activities, while p-nitrophenol hydroxylase (PNPH) was used as a marker of CYP2E1 activities. Of the steroids tested, only 17β-estradiol and 17α-estradiol inhibited EROD and MROD activities. This inhibition was observed when a steroid concentration of 100 μM was used, while lower concentrations showed no inhibitory effect. PNPH activities were inhibited only by 100 μM of 17β-estradiol. The significance of these results in vivo is unknown because inhibition was only found when concentrations of estrogens higher than physiological levels were used. Nevertheless, the results provided further evidence on the important role of estrogens in regulation of porcine cytochrome P450 activities.

References

Doran E, Whittington FW, Wood JD, McGivan JD. (2002). Cytochrome P450IIE1 (CYP2E1) is induced by skatole and this induction is blocked by androstenone in isolated pig hepatocytes. Chemico-Biological Interactions 140: 81-92.
Search in Google Scholar
Gillberg M, Skaanild MT, Friis C. (2006). Regulation of gender-dependent CYP2A expression in pigs: involvement of androgens and CAR. Basic Clinical Pharmacology and Toxicology 98: 480-487.
Search in Google Scholar
Gonzalez FJ. (2001). The use of gene knockout mice to unravel the mechanisms of toxicity and chemical carcinogenesis. Toxicology Letters 120: 199-208.
Search in Google Scholar
Gonzalez FJ. (2007). The 2006 Bernard B. Brodie Award Lecture - CYP2E1. Drug Metabolism and Disposition 35: 1-8.
Search in Google Scholar
Hobe G, Schön R, Goncharov N, Katsiya G, Koryakin M, Gesson-Cholat I, Oettel M, Zimmermann H. (2002). Some new aspects of 17α-estradiol metabolism in man. Steroids 67: 883-893.
Search in Google Scholar
Kojima M, Sekimoto M, Degawa M. (2008). A novel gender-related difference in the constitutive expression of hepatic cytochrome P4501A subfamily enzymes in Meishan pigs. Biochemical Pharmacology 75: 1076-1082.
Search in Google Scholar
Kojima, M., Sekimoto, M., Degawa, M. (2010). Androgen-mediated down-regulation of CYP1A subfamily genes in the pig liver. Journal of Endocrinology 207: 203-11.
Search in Google Scholar
Lu Y, Cederbaum AI. (2008). CYP2E1 and oxidative liver injury by alcohol. Free Radical Biology & Medicine 44: 723-738.
Search in Google Scholar
Rasmussen MK, Zamaratskaia G, Ekstrand B. (2010). Gender-related differences in cytochrome P450 in porcine microsomes - implication for activity, expression and inhibition by testicular steroids. Reproduction in Domestic Animals, doi: 10.1111/j.1439-0531.2010.1714.x. [Epub ahead of print].10.1111/j.1439-0531.2010.1714.x21091800
Search in Google Scholar
Rasmussen MK, Zamaratskaia G, Ekstrand B. (2011a). In vitro cytochrome P4502E1 and 2A activities in the presence of testicular steroids. Reproduction in Domestic Animals 46: 149-154.10.1111/j.1439-0531.2010.01613.x20403129
Search in Google Scholar
Rasmussen MK, Ekstrand B, Zamaratskaia G. (2011b). Comparison of cytochrome P450 concentrations and metabolic activities in porcine hepatic microsomes prepared with two different methods. Toxicology in Vitro 25: 343-346.10.1016/j.tiv.2010.10.00720940039
Search in Google Scholar
Rasmussen MK, Zamaratskaia G, Ekstrand B. (2011c). In vivo effect of dried chicory root (Cichorium intybus L.) on xenobiotics metabolising cytochrome P450 enzymes in porcine liver. Toxicology Letters 200: 88-91.10.1016/j.toxlet.2010.10.01821056093
Search in Google Scholar
Skaanild MT, Friis C. (2007). Is bupropion a more specific substrate for porcine CYP2E than chlorzoxazone and p-nitrophenol? Basic Clinical Pharmacology and Toxicology 101: 159-162.10.1111/j.1742-7843.2007.00083.x17697034
Search in Google Scholar
Tambyrajah WS, Doran E, Wood JD, McGivan JD. (2004). The pig CYP2E1 promoter is activated by COUP-TF1 and HNF-1 and is inhibited by androstenone. Archives of Biochemistry and Biophysics 431: 252-260.
Search in Google Scholar
Zamaratskaia G, Squires EJ, Babol J, Andersson HK, Andersson K, Lundström K. (2005). Relationship between the activities of cytochrome P4502E1 and P4502A6 and skatole content in fat in entire male pigs fed a diet with and without raw potato starch. Livestock Production Science 95: 83-88.
Search in Google Scholar
Zamaratskaia G, Chen G, Lundström K. (2006). Effects of sex, weight, diet and hCG administration on levels of skatole and indole in the liver and hepatic activities of cytochromes P4502E1 and P4502A6 in pigs. Meat Science 72: 331-338.
Search in Google Scholar
Zamaratskaia G, Gilmore WJ, Lundström K, Squires EJ. (2007). Effect of testicular steroids on catalytic activities of cytochrome P450 enzymes in porcine liver microsomes. Food and Chemical Toxicology 45: 676-681.
Search in Google Scholar
Zamaratskaia G, Oskam IC, Ropstad E, Tajet H, Andresen Ø. (2008). Effect of hCG stimulation on hepatic activities of cytochrome P4502E1 and P4502A in entire male pigs. Reproduction in Domestic Animals 43: 147-152.
Search in Google Scholar
Zamaratskaia G, Squires EJ. (2009). Biochemical, nutritional and genetic effects on boar taint in entire male pigs. Animal 3: 1508-1521.
Search in Google Scholar
Zamaratskaia G, Zlabek V. (2009). EROD and MROD as makers of cytochrome P4501A activities in hepatic microsomes from entire and castrated male pigs. Sensors 9: 2134-2147.
Search in Google Scholar
Zamaratskaia G, Zlabek V, Chen G, Madej A. (2009). Modulation of porcine cytochrome P450 enzyme activities by surgical castration and immunocastration. Animal 3: 1124-1132.
Search in Google Scholar

In vitro inhibition of porcine cytochrome P450 by 17β-estradiol and 17α-estradiol

Abstract

Paradigm

My account