Can Mammalian Eggs Undergo Normal Development in Vitro?

Abstract

Ten unfertilized ova were recovered from the fallopian tubes of an agouti rabbit 13 hrs. after copulation with a vasectomized English-spotted buck. Sperm from the vas deferens of a self-colored non-agouti black [male] were placed with those ova for 20 min., during which the surrounding granulosa mass disintegrated and the vitellus shrunk slightly[long dash]events ordinarily occurring during insemination. The eggs freed of surrounding spermatozoa were transferred to the fallopian tube of a New Zealand red doe rendered pseudopregnant by mating 48 hrs. previously with a vasectomized English-spotted [male]. 33 days later the New Zealand doe produced 7 dark gray young. If, by some chance, the vasectomized [male] had produced spermatozoa these young would have been English-spotted. Since the ova of pseudopregnant does are certainly not fertilizable by 24 hrs. after copulation and since the New Zealand red foster mother was mated not 24 but 48 hrs. before the transfer of ova, the young could not have arisen from the chance fertilization of her ova by spermatozoa accidentally introduced into the tubes with the transplanted ova. This is believed to be the first certain demonstration that mammalian eggs can be fertilized in vitro. In a 2d case, 5 ova obtained in the 1-cell stage from the tubes of an English doe mated to a agouti [male] were cultured in Carrel flasks for 20 hrs., then transplanted to the fallopian tube of an albino doe rendered pseudopregnant by copulation with a vasectomized black [male]. 2 gray English-spotted young were obtained 31 days after the transplantation. Incidentally, these expts. demonstrate that the corpora lutea of pseudopregnancy are fully functional.