Thrombospondin is sequentially expressed and then de-expressed during early pregnancy in the rat uterus

The expression of thrombospondin on Day 1, Day 3 and Day 6 of pregnancy has been examined in the rat, using light microscopic immunoperoxidase and electron immunogold techniques. The glycoprotein was expressed in the apical, lateral and basal uterine epithelium on Days 1 and 3 but was then de-expressed at the time of implantation on Day 6. We propose that these data suggest a role for thrombospondin in remodellig the uterine epithelium during the plasma membrane transformation, but that it does not play a part in attachment and implantation.