Abstract
Mouse blastocyst cultures were analyzed for concanavalin A (Con A) agglutinability by microhemadsorption methods and for con A binding capacity with rhodamine-con A stain. The inner cell mass [ICM], which was not agglutinable in the early culture stages, became agglutinable when it started to develop. The trophoblast, which was initially agglutinable, lost this property as the cells matured. There was no apparent correlation between changes in agglutinability and capacity to bind rhodamine-con A. The pattern of change in con A agglutinability which characterized development of the ICM and trophoblast was related to the migratory activities of these cells. The loss of agglutinability associated with trophoblast maturation may be due to alterations in Con A receptor accessibility.