Drug metabolic activity of cultured hepatocytes can synchronize with bile acid concentration in the medium.
The regulation of drug metabolic activity of cultured hepatocytes can be applied to the evaluation of pharmacokinetics, analysis of drug delivery and the bioartificial liver system. It is very difficult to maintain the drug metabolic activity mediated by cytochrome P-450 (CYP) 3A. Recently we found that the CYP3A aminopyrine N-demethylase (AMND) activity of hepatocytes cultured on collagen surface oscillated with culture time. This phenomenon was related to the concentration of bile acid in the culture medium. CYP3A, multidrug resistant gene 2 (MDR2) and heat shock protein 84 (HSP84) mRNA appeared in a manner corresponding to this oscillation. When a large quantity of bile acid was taken up into hepatocytes from the medium, low AMND activity was observed, and these proteins did not appear. When bile acid was secreted and the bile acid concentration inside the hepatocytes was low, high AMND activity was obtained, and these proteins appeared. In order to clarify the mechanism of oscillation between AMND activity and bile acid, 8 microM glycocholic acid was added to the culture medium 15 h before the measurement. No oscillation in AMND activity was observed in the presence of 8 microM glycocholic acid. Bile acid controls the AMND activity in the transcription of hepatocytes.
Sugihara
Nobuhiro
N
Graduate School of Medicine, Shinshu University, Asahi Matsumoto, Japan. sugihara@sch.md.shinshu-u.ac.jp
Ise
Hirohiko
H
Negishi
Naoki
N
Nikaido
Toshio
T
Akaike
Toshihiro
T
D000633:Aminopyrine N-Demethylase / Q000378:metabolism; D000818:Animals; D001189:Aryl Hydrocarbon Hydroxylases; D001647:Bile Acids and Salts / Q000378:metabolism*; D001683:Biological Clocks; D002478:Cells, Cultured; D003470:Culture Media; D051544:Cytochrome P-450 CYP3A; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism; D006000:Glycocholic Acid / Q000494:pharmacology; D022781:Hepatocytes / Q000187:drug effects / Q000378:metabolism*; D007700:Kinetics; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D010089:Oxidoreductases, N-Demethylating / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism
D001647:Bile Acids and Salts; D003470:Culture Media; D012333:RNA, Messenger; D003577:Cytochrome P-450 Enzyme System; D001189:Aryl Hydrocarbon Hydroxylases; D051544:Cytochrome P-450 CYP3A; D010089:Oxidoreductases, N-Demethylating; D000633:Aminopyrine N-Demethylase; D006000:Glycocholic Acid