Cell surface characteristics of blastocysts from spontaneously ovulating and gonadotropin-treated mice.

Differences were found in the surface architecture of blastocysts from spontaneously ovulating and from gonadotropin-treated females of the BALB/cBy and the C57BL/6J strains of mice. Significantly fewer microvilli and a greater percentage of smooth areas were found on the surfaces of blastocysts from gonadotropin-treated females compared to those from spontaneously ovulating females. The differences were greater in blastocysts from gonadotropin-treated immature females than in blastocysts from similarly treated mature females.