Influence of intra-uterine infusions of blastocyst tissue homogenate on the ultrastructure of spayed rabbit uterus.

Scanning electron microscopic observations were made on uterine horns of ovariectomized rabbits after intra-uterine infusions of preimplantation blastocyst tissue homogenate and on control uterine horns. After two successive infusions of 5 or 6 day embryo homogenate, the secretory activity of luminal and glandular cells was considerably stimulated. These findings showed that preimplantation blastocyst alone, in the absence of ovaries, could directly act upon endometrium. The nature of the active factor was discussed.