：Objective Leukemia inhibitory factor(LIF) is a pleiotropic cytokine which expresses in the mouse endometrium and plays an important role in implantation. In the present study we examined whether LIF of mouse embryos would express or not after implantation (5 th-

7 th-

10 th-12 th- and 15 th-day post coitus). Methods LIF transcripts for 50 embryos were dectected by reverse transcription-polymerase chain reaction (RT-PCR). Results LIF weak expressions in only 3 embryos (2 for 5th-day and 1 for 7th-day post coitus) were observed

but LIF expressions in the others from 10th-day to 15th-day post coitum were absent. Conclusion Our results suggested that LIF expression in the mouse embryo might be limited.