OBJECTIVE To determine if human oviduct expresses messenger ribonucleic acids (mRNAs) encoding insulin-like growth factor binding proteins (IGFBPs), if oviductal epithelium secretes IGFBPs into conditioned medium (CM), and if IGFBP secretion is regulated by steroid hormones. METHODS Northern blots of RNA, isolated from late proliferative phase human fimbria and oviductal isthmus, were probed with complementary deoxyribonucleic acids encoding IGFBP-1, IGFBP-2, IGFBP-3, and IGFBP-4. In addition, oviductal ampullary epithelial cells were cultured with and without estrogen and/or progesterone (P), and IGFBPs were examined in CM by Western ligand blot analysis and identified using specific antisera. METHODS Tissue was obtained from hysterectomy specimens at Stanford University Hospital, a private teaching institution. METHODS Patients undergoing hysterectomy for benign disease. METHODS None. METHODS Transcripts of IGFBP mRNA and IGFBPs secreted into CM were detected by autoradiography of Northern and Western ligand blots, respectively. RESULTS Messenger RNA transcripts encoding IGFBP-2, -3, and -4 were detected, whereas IGFBP-1 mRNA was barely detectable in oviductal tissue. In CM, IGFBP-2 and IGFBP-3 were detected, as was a unique 24-kd IGFBP, although IGFBP-1 was not observed. Estrogen and/or P did not regulate the secretion of these IGFBPs by cultured oviductal epithelium. CONCLUSIONS Human oviduct expresses mRNAs encoding IGFBP-2, IGFBP-3, and IGFBP-4, and in vitro oviductal epithelium secretes IGFBP-2, IGFBP-3, and a unique binding protein of 24 kd, which may be the recently identified IGFBP-4.