“The non-steroidal antioestrogen tamoxifen trans-1-(4-beta-dimethylaminoethoxyphenyl)-1,2-diphenylbut- 1-ene ), widely used in the treatment of breast cancer, and its oestrogenic cis-isomer rapidly inhibited contractile responses of isolated rat myometrium to supramaximal concentrations of oxytocin (1.28 X 10(-6) mol/l).”