We have studied the growth in culture of vascular smooth muscle cells (VSMC) from either spontaneously hypertensive rats or Wistar Kyoto (WKY) rats. VSMC from SHR proliferated more rapidly than cells from WKY, regardless of the media used. The incorporation of radioactive thymidine into DNA was also greater in SHR than in WKY. Of several growth factors tested, epidermal growth factor (EGF) had the greatest effect on proliferation. Specific ligand binding studies of radiolabeled EGF to quiescent VSMC showed that VSMC from SHR had both a greater affinity and a greater number of binding sites for EGF than cells from WKY. We are now determining levels of EGF receptor mRNA.
