A genomic approach to identify novel XXXX receptor regulated pathways in the uterus during implantation.

@entity172 @entity1420 @entity19 @entity134 @entity3927
The cellular actions of @entity134 hormone @entity1420 (P) are mediated via its nuclear receptors, which regulate the expression of specific target genes. The identity of gene networks that are regulated by the P receptors (PRs) in the uterus at various stages of the reproductive cycle and pregnancy, however, remain largely unknown. In this study, we have used oligonucleotide microarrays to identify mRNAs whose expression in the pregnant @entity19 uterus is modulated by @entity3927 , a well-characterized PR antagonist, which is also an effective inhibitor of implantation. We found that, in response to @entity3927 , expression of mRNAs corresponding to 78 known genes was down-regulated at least 2-fold in the preimplantation @entity19 uterus. The PR regulation of several of these genes was ascertained by administering P to ovariectomized wild-type and PR knockout (PRKO) @entity19 . Detailed spatio-temporal analysis of these genes in the pregnant uterus indicated that their expression in the epithelium and stroma could be correlated with the expression of PR in those cell types. Furthermore, time-course studies suggested that many of these genes are likely primary targets of PR regulation. We also identified 70 known genes that were up-regulated at least 2-fold in the pregnant uterus in response to @entity3927 . Interestingly, initial examination of a number of @entity3927 -inducible genes reveals that their uterine expression is also regulated by @entity172 . The identification of several novel PR-regulated gene pathways in the reproductive tract is an important step toward understanding how P regulates the physiological events leading to implantation.
