Expression changes of CYP2A and CYP3A in microsomes from pig liver and cultured hepatocytes.
The P450 enzymes of the liver are responsible for the metabolism of a wide range of chemical compounds, and hepatocytes are used in pharmacological and toxicological in vitro tests. Thus, it is important to know how stable these enzymes are in culture. We measured the activity of CYP2A and CYP3A in microsomes isolated from both pig liver and primary pig hepatocyte cultures, together with the apoprotein concentration using Western blotting. The CYP2A activity and apoprotein concentration decreased rapidly; only about 5 percent remained after 48 hr incubation, whereas the CYP3A activity and apoprotein concentration was constant. CYP3A was induced 3 times after exposure to rifampicin, whereas neither rifampicin nor pyrazole could induce CYP2A. The hepatocytes were also incubated with varying concentration of FCS and autologous serum, however without effect on the stability of CYP2A, nor did different concentrations of growth hormone and testosterone added to the cultures have any effect.
Skaanild
M T
MT
Department of Pharmacology and Pathobiology, The Royal Veterinary and Agricultural University, Copenhagen, Denmark. mts@kvl.dk
Friis
C
C
D000818:Animals; D001059:Apoproteins / Q000378:metabolism; D001189:Aryl Hydrocarbon Hydroxylases; D002478:Cells, Cultured; D051544:Cytochrome P-450 CYP3A; D065607:Cytochrome P-450 Enzyme Inhibitors; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D005260:Female; D022781:Hepatocytes / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D008862:Microsomes, Liver / Q000187:drug effects* / Q000201:enzymology* / Q000378:metabolism; D010089:Oxidoreductases, N-Demethylating / Q000037:antagonists & inhibitors* / Q000378:metabolism; D011720:Pyrazoles / Q000494:pharmacology; D012293:Rifampin / Q000494:pharmacology; D013250:Steroid Hydroxylases / Q000037:antagonists & inhibitors* / Q000378:metabolism; D013552:Swine
D001059:Apoproteins; D065607:Cytochrome P-450 Enzyme Inhibitors; D004791:Enzyme Inhibitors; D011720:Pyrazoles; C031280:pyrazole; D003577:Cytochrome P-450 Enzyme System; D013250:Steroid Hydroxylases; D001189:Aryl Hydrocarbon Hydroxylases; D051544:Cytochrome P-450 CYP3A; C022657:steroid hormone 6-beta-hydroxylase; D010089:Oxidoreductases, N-Demethylating; D012293:Rifampin