Growth factor-induced modulation of endothelin-1 binding to human smooth-muscle cells.

Endothelin-1 (ET-1) has been shown to cooperate with other growth factors to enhance mitogenesis of fibroblasts and vascular smooth-muscle cells (SMCs) in vitro. One possible mechanism underlying such enhancement is the comodulation of receptor density/affinity for one factor by the other. In previous work, we showed that pretreatment of Swiss 3T3 fibroblasts with such growth factors as epidermal growth factor (EGF), platelet-derived growth factor (PDGF), or basic fibroblast growth factor (bFGF) resulted in increased binding of 125 I-ET-1 to these cells by two-, four-, and fivefold, respectively