Changes in secreted uterine proteins associated with embryo implantation in the mouse

A dual-label ratio method was used in conjunction with two-dimensional polyacrylamide gel electrophoresis to measure the relative changes in rates of production of individual secreted proteins by mouse uteri at the start of the process of decidualization. A characteristic pattern of differential changes in the rate of synthesis and secretion of the proteins was found to be associated with development of a positive Pontamine Blue reaction at the site of embryo implantation. These changes were compared with those associated with development of experimentally induced deciduomata and although the patterns were similar, presumably reflecting common processes in transformation of the endometrium, there was preferential enhancement of a subset of small (Mr 14,000-20,000) acidic proteins in the authentic implantation sites. It is suggested that this embryo-dependent modification of constitutive changes associated with decidualization reflects a form of embryo-maternal signal-response mechanism that may be important for the process of implantation in mice.