[Morphologic and histochemical characteristics of mammalian embryos during the pre-implantation period of development].

Submicroscopic embryo organization during preimplantation development was analyzed and its carbohydrate metabolism at these stages was studied. In the process of investigation the following regularities were revealed: progressive rearrangement of the nucleus (from compact to reticular); alterations in cytoplasmic structures (in multivesicular bodies, in autophagal vacuoles, in mitochondria, in granular cytoplasmic network, in lamellar structures); complication of intracellular interrelations (by means of microvilli and median bodies at early stages and during subsequent formation of cellular processes, contacts after "thorn--net" pattern, dense, fissure-like contacts and desmosomes). By means of cytochemical and electron histochemical methods, glycogen distribution in embryos at different stages of development was elucidated, and tendency to its decrease with the progress of the development was noted, with its least contents being at the stage of blastocyst.