Expression of Leptin Receptor at Implantation Sites Compared to Interimplantation Sites in the Mouse Uterus

1. Leptin itself was not expressed in mouse uterine tissues. 2. Leptin receptors were not expressed in nonpregnant and little expressed in 3.5 day of pregnant uterine tissues. However, there was a signal in 4.5 and 5.5 day of tissues. 3. The expression level of leptin receptor variants in the implantation sites at around the time of initial embryo attachment (day 4.5 of pregnancy) and during the actual implantation period (day 5.5 of pregnancy) was much lower than that in the interimplantation 4. Finding of the differential expression of leptin receptors in implantation sites compared to interimplantation sites suggests that leptin - leptin receptor system may be one of the delicate regulators in the molecular mechanism of the implantation process.