Viability and Developmental Capacity of Eggs from Immature Mice treated with Gonadotrophins

Abstract

SEXUALLY immature mammals induced to superovulate and mate following gonadotrophin treatment provide a convenient supply of fertilized mammalian eggs for experimental purposes. The time of their ovulation is known and is independent of diurnal regulation. The large number of eggs recoverable from a single superovulated female can be expected to contain less genetical and physiological variability than an equal number from several mature donors. Also, when egg recovery necessitates killing females, the economy of using immature animals is realized in greater egg productivity and in a shortened generation interval. It is important, therefore, to establish whether eggs from ovulations induced in immature females are of normal viability and developmental capacity. Previous evidence^1–3 on this problem is not decisive in that it lacks direct comparisons with spontaneously ovulated eggs, from adult females, developing in similar uterine environments. The present work was intended to meet these requirements.