Abstract: Objective To evaluate the production and regulation of platelet-derived growth factor (PDGF) in the skin. Methods Normal human keratinocytes (NHKs) and human dermal fibroblasts (HDFs) were cultured, PDGF peptides were measured by ELISA and PDGF-B chain mRNA was detected by Northern hybridization. Results The results showed that NHKs constitutively produced PDGF molecules, phorbol 12-myristate 13-acetate (PMA) inhibited PDGF production, while 1, 25-dihydroxyvitamin D₃ enhanced its production. TNF-alpha, interferon-γ and interleukin-1 alpha all failed to affect PDGF production. On the other hand, HDFs produced no PDGF molecule in spite of a low level of PDGF-B chain mRNA expression in Northern hybridization, suggestting a post-transcriptional blocking of PDGF production in HDFs. Conclusion The results obtained above indicate that epidermal keratinocytes may be the major PDGF-generating cells, whereas dermal fibroblasts the PDGF-responsive cells in the skin.

Key words: Keratinocytes, Fibroblasts, Platelet-derived growth factor