[Regulation by Maternally Derived Cytokines of Pre-implantation Development and Uterine Receptiveness]

Increasing evidence is revealing that cytokines, under the control of steroid hormones, are important in regulating fetal-maternal interactions during pregnancy. Mice carrying mutated genes coding for these factors or their receptors, have been instrumental in clarifying the in vivo roles of these factors in reproduction. Lack of many of the cytokines expressed in the male and female reproductive tracts, such as TNF-alpha, Inf-gamma, the majority of the interleukins and the transforming growth factors TGF-alpha and beta do not result in any gross impairment in reproductive efficiency. However, some cytokines do have a critical role, in particular Leukemia Inhibitory Factor (LIF), Colony stimulating Factor-1 (CSF-1), Epidermal Growth Factor (EGF) and possibly interleukin-1 (IL-1). The recent advances relating to the reproductive roles of these factors up to the time of embryo implantation will be discussed.