Comparative analysis of CYP3A expression in human liver suggests only a minor role for CYP3A5 in drug metabolism.

To study mechanisms behind the interindividual variability in CYP3A expression and the relative contribution of the different CYP3A enzymes to the overall CYP3A activity, we have analyzed CYP3A4, CYP3A5, CYP3A43, and PXR mRNA and CYP3A4 and CYP3A5 protein expression, catalytic activity, and polymorphism in the CYP3A5 gene in a panel of 46 Caucasian human livers. Protein quantification was performed by Western blotting using enzyme-specific antibodies directed to the C termini of CYP3A4 or CYP3A5, and carrier protein-coupled peptides as standards. The mRNA levels were determined by quantitative real-time PCR.

Recent Progress in Drug Metabolism Research.

The 14th International Symposium on Microsomes and Drug Oxidations was held July 22­26, 2002, in Sapporo, Japan. The meeting included 13 plenary sessions, 75 symposia lectures and about 200 poster presentations, and covered a wide variety of topics on general, clinical and toxicologic aspects of drug metabolism. Highlights of the meeting are discussed.