mRNA expression levels of cytochrome P450 , , and in the epidermis: a focus on individual differences among Japanese individuals.

Various cytochrome P450 enzymes (CYPs) that contribute to drug metabolism are expressed in the skin. However, variation among individuals in CYP expression profiles is not well-understood.To investigate CYPs related to the metabolism of transdermal preparations in Japan, multiple skin tissue specimens of individuals of Japanese descent were prepared, and the mRNA expression levels of , , and were measured. Associations between the expression patterns of these CYPs and body mass index (BMI) were also investigated.There were considerable individual differences in epidermal mRNA expression levels, and showed a weak positive correlation with mRNA expression levels. In contrast to previous results for other organs, epidermal mRNA expression levels showed a weak positive correlation with BMI. in the epidermis may have been locally enhanced as a defence mechanism against xenobiotics in response to impaired barrier function. These differences in mRNA expression in the skin may affect the transdermal absorption of drugs, such as lidocaine and fentanyl, which are metabolised by multiple overlapping CYPs.Our study provides new insights into drug metabolism in the skin. These results are valuable for predicting drug effects and transdermal drug transfer rates in Japanese patients.