To quantitate 2-methoxyestradiol (2-ME) in human corpus luteum (CL) of different ages and to determine the expression of cytochrome-P450-1A1 (CYP1A1) and catechol-O-methyl transferase (COMT) in CL and the action of 2-ME on P, vascular endothelial growth factor (VEGF) secretion, and luteal angiogenesis. Plasma levels of E2 decreased in the late luteal phase in association with an increase in luteal tissue of 2-ME concentrations. Concomitantly, there was a significant reduction of angiogenic activity in late CL. There was no significant variation in CYP1A1 and COMT expression in all CL. In physiological doses, 2-ME inhibited basal VEGF by granulosa lutein cells and diminished the angiogenic activity in conditioned media but did not prevent P and VEGF production stimulated by hCG.