Effects of treating females with exogenous gonadotropins on the ultrastructure of mouse embryos and oocytes

Todd Astor


Differences were found in the cell surface ultrastructure of oocytes and embryos from mature, spontaneously ovulating and from immature, gonadotropin-treated females of the C57BU6J strain of mice. Significantly fewer microvilli were found on the surfaces of unfertilized oocytes, 2-cell embryos, and 8-cell embryos from gonadotropin-treated females compared to that found on the surfaces of oocytes and embryos from spontaneously ovulating females. This difference may account for the observation that embryos from gonadotropin-treated females implant with less success than embryos from spontaneously-ovulating females.