BACKGROUND: Endothelins, potent stimulators of smooth muscle tissue activity, were recently shown to also function as mitogens for numerous cell types. The authors investigated the properties of endothelin-1 (ET-1) receptors in human endometrial tissue compared with human endometrial carcinoma tissue. METHODS: Tissue samples from 13 patients with endometrial carcinoma and from 12 women undergoing hysterectomy due to uterus myomatous were obtained immediately after surgical removal. Binding properties of the endothelin receptors were studied using 125I-labeled ET-1. RESULTS: A significant difference was demonstrated between binding properties of ET-1 receptors of these two groups. The mean maximal density (Bmax) value of the normal endometrial samples was 2029 +/- 341 fmol/mg protein, whereas that of the neoplastic samples was 356 +/- 121 fmol/mg protein. No differences were found, however, between the mean dissociation constant (Kd) values of these groups. CONCLUSIONS: These results might be compatible with the increased blood flow that characterizes malignant endometrial tissue. However, they do not indicate an important mitogenic role for ET-1 in the development of endometrial cancer.
BACKGROUND: Endothelins, potent stimulators of smooth muscle tissue activity, were recently shown to also function as mitogens for numerous cell types. The authors investigated the properties of endothelin-1 (ET-1) receptors in human endometrial tissue compared with humanendometrial carcinoma tissue. METHODS: Tissue samples from 13 patients with endometrial carcinoma and from 12 women undergoing hysterectomy due to uterus myomatous were obtained immediately after surgical removal. Binding properties of the endothelin receptors were studied using 125I-labeled ET-1. RESULTS: A significant difference was demonstrated between binding properties of ET-1 receptors of these two groups. The mean maximal density (Bmax) value of the normal endometrial samples was 2029 +/- 341 fmol/mg protein, whereas that of the neoplastic samples was 356 +/- 121 fmol/mg protein. No differences were found, however, between the mean dissociation constant (Kd) values of these groups. CONCLUSIONS: These results might be compatible with the increased blood flow that characterizes malignant endometrial tissue. However, they do not indicate an important mitogenic role for ET-1 in the development of endometrial cancer.