Action of oestrogen on the blastocyst and uterus in delayed implantation- an autoradiographic study

Abstract

The metabolic changes in the pre-implantation blastocyst have been studied by instillation of ³H-cytidine, ³H-phenyl alanine and ³H-thymidine into the uterine lumen in experimentally induced delayed implantation and at specific time intervals after the administration of oestrogen. Minimal RNA synthesis occurs in the blastocyst and uterus during delayed implantation. Minimal protein synthesis is seen only in the uterine epithelium during this period. Oestrogen enhances the synthesis of RNA, DNA and protein in the blastocyst while only RNA and protein synthesis are activated in the uterus. The significance of these oestrogeninduced changes in the blastocyst and uterus is discussed in relation to implantation.