BINDING AND TYROSINE KINASE-ACTIVITY OF INSULIN-RECEPTOR IN HUMAN NORMAL AND NEOPLASIC ENDOMETRIUM

Endometrial carcinoma represents 4.3% of all female malignant tumors i n South Brazil. Insulin, epidermal growth factor (EGF) and insulin-lik e growth factor I (IGF-I) may be involved in the neoplastic endometria l proliferation. Insulin binding and receptor tyrosine kinase activity were investigated in endometrial carcinomas and in normal endometrium . The insulin receptor (IR) concentration, as showed by binding assays with microsomes, was similar in normal tissue (3.4+/-2.5 fmol mu(-1)) and carcinomatous endometrium (2.1+/-1.4 fmol mu g(-1)). There was a higher affinity of the IR to insulin in the carcinoma group, but this difference was not statistically significant. There was no significant difference between normal and neoplasic endometrium in the phosphoryl ation of the IR beta subunit (180.4+/-15.5) cpm and 191.1+/-13.7 cpm, respectively). Understanding the metabolism of the neoplastic cells co ntribute to the development of prevention strategies as well as new th erapeutics.