Abstract
Transthyretin (TTR), a carrier for thyroxine and retinol, has its messenger RNA (mRNA) expressed in the glandular endometrial epithelium and its protein detected in the glandular endometrial epithelium and the uterine lumen. TTR mRNA is dramatically up-regulated in the preimplantation mouse uterus as well as the P-treated ovariectomized mouse uterus, and in both situations the up-regulation of TTR is blocked by treatment with the P receptor antagonist RU486.