RECOVERY OF BLASTOCYSTS AND INDUCTION OF IMPLANTATION FOLLOWING ARTIFICIAL INSEMINATION OF IMMATURE MICE

Abstract

Prepuberal female mice were hormonally induced to ovulate and were artificially inseminated with spermatozoa that had been stored in vitro from 2 to 24 hr. No difference was found in fertilizing ability due to storing spermatozoa for different periods of time. Inseminations were performed at various times relative to ovulation, ranging from 2 hr before ovulation to 13 hr after ovulation. The time of insemination relative to ovulation did influence the percentage of ova that were blastocysts and it appeared that the optimum time for insemination is about 6 hr after ovulation. Blastocysts were recovered from females following insemination up to 13 hr after ovulation. Blastocysts were capable of implantation and developing to 18-day foetuses under the stimulus of progesterone administered orally to the mice. Blastocysts produced by artificial insemination of prepuberal mice are capable of implantation and development after a delay in implantation of at least 11 days. Further refinements of the techniques described may permit more detailed study of the viability of germ cells produced and handled under a wide variety of conditions.