Condition-dependent presence of beta-lipotropin-like peptide in human keratinocytes

This study aimed to characterize the beta-endorphin-immunoreactive material (beta E-IR) detectable in normal human keratinocytes (NHK). The effects of different culturing conditions and UV-irradiation on production of beta E- IR by NHK were assessed by radioimmunoassay and HPLC. All culture systems c ontained low levels of beta E-IR that was increased in conditioned media af ter UV-irradiation under certain conditions. NHK grown in nutrient-poor med ium contained highest levels of beta E-IR that exhibited beta-lipotropin-li ke properties after HPLC analysis. The other culturing conditions displayed no authentic beta E-related peptides. Our results indicate that under cert ain culturing conditions NHK can produce POMC peptides like beta-lipotropin , which can be induced by UV-radiation. (C) 2000 Elsevier Science Inc. All rights reserved.