Interaction of o, p'DDT with the estrogen-binding protein (EBP) in human mammary and uterine tumors.

The in vitro effect of o, p'DDT on the binding of 3H-estradiol-17beta (3H-E2) to the high affinity estrogen-binding protein(EBP) in cytosol derived from human mammary and uterine tumors was examined. o,p'DDT inhibited the binding of 3H-E2 to EBP in both breast and uterine tumors. Using Scatchard and Linweaver-Burk plot analyses, the inhibition by o,p'DDT of 3H-E2 binding to mammary tumors EBP appears to result from competition for the 8S moiety binding sites and not from deactivation of the binding sites. The KI for the inhibition by o,p.'DDT with EI binding was determined, yielding a value of 0.5 +/- 0.1 muM. The possible relevance of these findings to human population exposed to DDT derivatives is discussed.