Taurine modulates induction of cytochrome P450 3A4 mRNA by rifampicin in the HepG2 cell line.

Taurine is not only present in foods, tonics and nutrient drinks but is also used as a medicinal agent mainly for treatment of chronic heart failure and liver disease. However, little is known about its influence on drug-metabolizing enzymes, especially cytochrome P450 (CYP), in human. We examined whether taurine could affect the expression of CYP3A4 mRNA in the presence or absence of rifampicin (RFP), which is a potent inducer of CYPs, with HepG2 cells. Taurine enhanced twice the induction of CYP3A4 mRNA by RFP, but did not affect the expression by itself. This effect was both concentration- and time-dependent. On the other hand, taurine did not affect the induction by phenobarbital. Taurine did not increase intracellular uptake of RFP. Therefore, we conclude that taurine is an enhancer for the induction of CYP3A4 by RFP.