SPECIES-SPECIFICITY OF TRIPHENYLETHYLENE DERIVATIVES AND OF COMPOUNDSWITH A STEROIDAL BACKBONE FOR HUMAN AND RAT-LIVER ANTIESTROGEN BINDING-SITE (AEBS)

The binding affinity of derivatives of the triphenylethylene (TPE) ant ioestrogen tamoxifen and of steroidal compounds for human liver antioe strogen binding sites (AEBS) was compared with their binding affinity for mt liver AEBS. Despite the observation of some quantitative differ ences overall a highly significant correlation between the relative bi nding affinity (RBA) for human and rat fiver AEBS was found for all co mpounds tested (r = 0.93, N = 19, P < 0.001). This was more pronounced for TPE derivatives (r = 0.83, N = 12, P < 0.01) than for cholesterol derived compounds (r = 0.64, N = 7, not significant). We conclude tha t AEBS from rat liver can be used instead of human livers as a model t o study the interactions of antioestrogens with AEBS.