Endothelin-1 secretion by human fibroblasts in culture: effects of cell density and IFN-beta

Evidence is presented of ET-1 release by cultured human fibroblasts. Such a conclusion is supported by the parallelism in displacement curves obtained using dilutions of extracts prepared from fibroblast conditioned media and the synthetic ET-1 standards, and the significant time dependent increase in ET-1 content in media from IFN-beta treated human fibroblasts. An increase in cell density significantly elevated the total amount of ET-1 in the conditioned media, although a linear relationship between these two variables was not observed.