Mepartricin is estrogen reabsorption inhibitor that may interfere with the reabsorption of estrogens in the gut leading to increased fecal estrogen excretion. It reduces 17 β estradiol concentration in enterohepatic circulation and decreases estrogen levels in the prostate. The effect of mepartricin on the reabsorption of estrogens was evaluated in studies in vitro and in vivo.