Spontaneous Activation of the Hamster Eggin vivo

Abstract

Spontaneous activation of the hamster ovum is a normal occurence in oviducal eggs that are not inseminated. Many aspects comprising this process of parthenogenesis mimic events characteristic of fertilization and include for example, the formation of the second polar body and the development of one or two pronuclei. Occasionally the activated egg cleaves to form a two-cell stage. The similarity between the spontaneously activated hamster ovum and the inseminated egg has been previously documented at the light microscopic level of investigation; however, further investigation is warranted for the study of parthenogenesis in mammals provides an opportunity of elucidating developmental mechanisms of the fertilized egg. Accordingly, unfertilized eggs were flushed from the oviducts of hamsters at different intervals during the estrus cycle (6 to 70 hours postovulation), prepared for light and electron microscopy, and compared with fertilized eggs obtained at corresponding periods.