Leptin is critical for successful implantation in mice

Leptin, a 16kDa polypeptide, has long been known to have a role in reproduction as exogenous leptin administration can reverse the sterility of ob/ob mice which lack functional leptin. Leptin binds to cell surface receptors (Ob-R) and signals via STAT/JAK signal transduction pathway. This ligand receptor system is mandatory for embryonic implantation in rodents as withdrawl of leptin infusion in ob/ob females shortly after fertilization impairs implantation. Leptin and its receptors are expressed in human and mouse endometrium. Leptin has been immunolocalized in human and mouse preimplantation embryos and promotes mouse preimplantation embryo development through Ob-R signaling. The aim of our experiment was to study the impact of blocking leptin signaling in the mouse endometrium by giving intrauterine injections of leptin antiserum on day 1 and day 3 of pregnancy.