Résumé : The ovarian renin-angiotensin system is involved in various aspects of human reproduction. As immunoreactive measurement of angiotensin II (ANG II) in follicular fluid (FF) relates to several angiotensin peptides with different biological activities, HPLC was used to characterize the molecular forms of the ANG II immunoreactivity in human FF. Samples of FF, obtained from gonadotropin-stimulated patients for in vitro fertilization, were collected at the time of oocyte retrieval. The C-terminal 2-8 heptapeptide was never detected. HPLC analysis revealed for the first time that the major component of the ANG II-IR in human FF was the biologically active octapeptide ANG II.