Changes in Glycoconjugates on the Cell-Surface of Mouse Embryos in the Course of Blastocyst Formation. A Lectin-Histochemistry.

Peroxidase-conjugated lectins were used to examine histochemical changes in glycoconju-gates on the cell-surface of mouse embryos in the course of blastocyst formation. The binding of PNA, GS-l, DBA, SBA, WGA and FBP was observed in all the blastomeres of embryos at the stages of 8-cell to blastocyst, but LPA binding was not. The UEA-l binding was found in the blastomeres of uncompacted 8-16 cell embryos, in flattend blastomeres of compacted 8-16 cell embryos, and in trophoblast cells of blastocysts, but not in round blastomeres of compacted 8-16 cell embryos nor in inner-cell-mass cells of blastocysts. The binding of GS-ll, BPA, MPA or Con A was found in all the blastomeres of uncompacted and compacted 8-cell embryos, in flattened blastomeres of compacted 16-cell embryos, but not in round blastomeres of compacted 16-cell embryos. In blastocysts, the binding of BPA, MPA or Con A was found in trophoblast cells only, though that of GS-ll was not in trophoblast cells and inner-cell-mass cells. These findings imply that loss of the binding of UEA-l, GS-ll, BPA, MPA or Con A in round blastomeres of compacted embryos must be a participating factor in blastocyst formation.