Expression of progesterone receptor in human keratinocytes

Despite the various responses of human skin to female sex hormones, cellula r and subcellular targets and the mechanisms of action of estrogen and prog esterone in human skin are not well understood. The detection of estrogen r eceptor (ER) and progesterone receptor (PR) in the skin is of great importa nce to understand the effect of estrogen and progesterone. In primary cultu res of human keratinocytes, expression of ER and PR was monitored by immuno cytochemistry and reverse transcriptase polymerase chain reaction (RT-PCR). Paraffin embedded skin tissues were stained with monoclonal antibodies to human ER and PR by immunohistochemistry. Cultured human keratinocytes expre ssed cytoplasmic PR protein and PR mRNA transcripts. By contrast, ER was de tected only at the mRNA level. Suprabasal keratinocytes from samples of pru ritic urticarial papules, plaques of pregnancy (PUPPP) and psoriasis were s tained positively only for PR, white those from samples of erythema nodosum were negative for both ER and PR. Lesional epidermis of PUPPP showed posit ive PR immunoreactivity, while nonlesional epidermis did not. No other cell s in the normal human skin were stained with ER and PR. The present study s uggests that by expressing PR human keratinacytes act as targets for proges terone action.