STIMULATION OF PROTEIN-KINASE-A ACTIVITY AND INDUCED TERMINAL DIFFERENTIATION OF HUMAN SKIN FIBROBLASTS IN CULTURE BY LOW-FREQUENCY ELECTROMAGNETIC-FIELDS

In the present study experiments are described, which indicate that th e exposure of normal human skin fibroblasts (HSFs) to a low-frequency electromagnetic field of 20 Hi and 7-8 mT does induce terminal differe ntiation within 14 days of daily exposure of 12 h. As demonstrated by the analysis of the expression level of the proto-oncogene c-myc, the induction of terminal differentiation of progenitor fibroblasts to pos tmitotic fibrocytes does most likely not involve changes in the c-myc protein. As one possible candidate being involved in the ELF-EMF-media ted inhibition of fibroblast growth and the subsequent induction of te rminal differentiation the cyclic AMP-dependent protein kinase A (PKA) could be characterised. Thus, the data presented clearly indicate tha t the specific EMF field of 20 Hz and 7-8 mT significantly interfere w ith regulatory processes of fibroblast proliferation and differentiati on. (C) 1998 Elsevier Science Ireland Ltd. All rights reserved.