Epoxide hydrolase activity in human skin.

1 Epoxide hydrolase (EH) activity was measured in biopsied skin (n = 42) using 7-[H3]-styrene oxide as substrate, and separation of the products by high performance liquid chromatography. 2 EH activity (mean +/- s.d.) was present in separated epidermis (139 +/- 105 pmol glycol formed mg-1 min-1) and dermis (165 +/- 120 pmol glycol formed mg-1 microsomal protein min-1). 3 Whole skin EH activity (mean +/- s.d.) varied widely (433 +/- 254 pmol glycol formed mg-1 microsomal protein min-1) 4 No significant difference in EH activity was observed in skin from breast, penis and leg. 5 Skin EH activity does not appear to contribute significantly to the systemic metabolism of epoxide, but may be important in determining the effects of epoxides formed within the epidermis.