Prostaglandins regulate a wide number of physiological functions. Recently PGF 2a analogue such as latanoprost was shown to have a real impact on hair regrowth. The aim of this study was to investigate and describe the expression profile in human hair follicle of prostaglandin metabolism key enzymes, i.e. carbonyl reductase-1 (CBR1), microsomal prostaglandin E synthase-1 (mPGES-1) and microsomal prostaglandin E synthase-2 (mPGES-2), cytosolic prostaglandin E synthase (cPGES), the aldoketoreductase AKR1C1 and the prostaglandin F synthase AKR1C3. Quantitative RT-PCR on plucked hair follicles revealed some sex-related differences, mPGES-2 and AKR1C3 expression levels being higher in women. Cell and hair follicle compartment specificity was investigated using Western blot, PGE 2 and PGF 2a ELISA assays and immunohistochemistry. Most of the hair cell types were endowed with prostaglandin metabolism machinery and were thus able to produce PGE 2 and ⁄ or PGF 2a . The epithelial part of the hair bulb was identified by immunohistology and EIA assays as the main source of prostaglandin synthesis and interconversion. All these observations support the concept that prostaglandins might be involved in hair growth and differentiation control.