Leukemia inhibitory factor in human reproduction

Objective: To describe the clinical findings, expressions, interactions, an d clinical implications of leukemia inhibitory factor (LIF) in human reprod uction. Design: Review of published articles. Setting: Clinical development unit of biotechnology company. Intervention (s): None. Result(s): In the endometrium, LIF is expressed in a menstrual cycle-depend ent manner, with the highest level occurring at the time of implantation. L IF is also detected in uterine flushing, and its level is significantly low er in women with unexplained infertility. Likewise, endometrial explants de rived from women with unexplained infertility showed reduced levels of LIF secretion. Binding of LIF to LIF receptor and gp130 activates signal transd uction pathways. LIF receptor is expressed in endometrium, oocytes, and bla stocysts. Cytotrophoblasts cultured in the presence of LIF differentiate to ward an anchoring extravillous phenotype. Conclusion(s): On the basis of reports gathered from animal and human studi es, LIF appears to play an important role in implantation and in the establ ishment of pregnancy. (Fertil Steril (R) 2001;76:1091-6. (C) 2001 by Americ an Society for Reproductive Medicine.).