Analysis of epidermal growth factor (EGF) receptor and effect of EGF on the growth of cultured Graves' and non-neoplastic human thyroid cells.

We analyzed epidermal growth factor receptors (EGF-R) and the growth stimulatory effects of epidermal growth factor (EGF) in the presence or absence of TSH on cultured human non-neoplastic and Graves' thyroid cells. All cells studied possessed EGF-R composed of two components. There was no significant differences in the binding characters of EGF-R among non-neoplastic thyroid cells whether they were obtained from thyroid tissues adjacent to malignant carcinoma or benign adenoma. Ten nM of EGF stimulated (3H)-thymidine (dTR) incorporation of non-neoplastic thyroid cells by about 50%. However, TSH had no effect on the growth of these cells. Both EGF-R binding parameters and cell proliferation effects of EGF and TSH were simultaneously examined in non-neoplastic thyroid cells from 8 patients. A significant inverse correlation (r = -0.757) was observed between binding affinity (Ka1) and EGF-induced increase of dTR incorporation. Binding capacity (Cmax) did not correlate significantly with dTR incorporation. In Graves' thyroid cells, all parameters of EGF-R were significantly lower than those of non-neoplastic thyroid cells, higher basal dTR incorporation was observed, and their goiter size significantly correlated with EGF-induced increase of dTR incorporation (r = 0.879) and also appeared to correlate inversely with Ka1. These data indicate a close relationship between the binding affinity of EGF-R and thyroid cell growth.