Synthesis and regulation of leukaemia inhibitory factor in cultured bovine oviduct cells by hormones

Abstract

Leukaemia inhibitory factor (LIF) is an essential factor for embryo implantation. Factors generated by the oviduct cells (epithelial cells and fibroblasts) create the microenvironmenttfor fertilization and first embryo stage development. Hence, it is feasible that the oviduct cells also synthesize LIF to to promote and condition the embryo for implantation in the uterus. In the present study, we investigated whether cultured bovine oviduct epithelial cells and fibroblasts synthesize LIF LIF production was measured in the conditioned medium of oviduct epithelial cells and fibroblasts, using LIF enzyme-linked immunosorben assay. Moreover, expression of LIF mRNA was confirmed by LIF reverse transcriptase-polymerase chain reaction in extracts of RNA from oviduct epithelial/fibroblast cells. Quantitatively similar amounts of LIF were detected in the culture medium of epithelial cells and fibroblasts. In cells cultured for 1-7 days, the levels of LIF in the medium increased in a time-dependent manner. As compared to untreated cells, treatment of cell with 178-oestradiol (1-100 ng/ ml), but not progesterone (1-100 ng/ml) and insulin (20 ng/ml), increase the of levels LIF in a concentration dependent manner (P < 0.05). Similarly, tumour necrosis factor- α (100 ng/ml)significantly induced the levels of LIF The effects of 17β- oestradiol (50 ng/ml) on LIF synthesis were enhanced not blocked in the presence of tamoxifen (1 μg/ml), an oestrogen receptor antagonist, suggesting that the stimulatory effects of 1713-oestradiol on LIF synthesis are not receptor-mediated. In conclusion 17β-oestradiol, but not progesterone, induces LIF synthesis by bovine oviduct epithelial cells and fibroblasts and this may play an important role in the biology of early embryo development. However, the exact pathophysiological role of LIF within the oviduct needs to be further investigated.