There are studies which indicate that some steroid derivatives have inotropic activity; nevertheless, there is scarce information about of themolecular mechanism involved at cardiovascular level. Therefore, in this study anestradiol derivative was synthetized with the objective of evaluating its inotropic activity. In the first stage, the Langendorff technique was used to measure changes on perfusion pressure and coronary resistance in an isolated rat heart model in absence or presence of estradiol and its derivative.In second stage, the inotropic activity of estradiol derivative was evaluated by measuring left ventricular pressure in absence or presence of following compounds; tamoxifen, prazosin, metoprolol, indomethacin and nifedipine. The results showed that the estradiol derivative significantly increases the perfusion pressure and coronary resistance in comparison with estradiol and the control conditions. Additionally, other data indicate that estradiol derivative increase left ventricular pressure in a dose-dependent manner [0.01 nM to 100 nM]; nevertheless, this phenomenon was significantly inhibited by tamoxifen at a dose of 1 nM. In conclusion, experimental data suggest that, inotropic activity positively induced by estradiol derivative on the left ventricular pressure may involve estrogen receptor activation.Author(s): Figueroa V. Lauro, DÃaz C. Francisco, GarcÃa C. Elodia, Pool G. Eduardo, LÃ³pez R. Maria, Rosas-Nexticapa M, Mendoza-LÃ³pez R, May G. Ivan, Sarao Ana.