Bioscientifica Proceedings

Uterine differentiation in cattle and sheep begins prenatally, but is completed postnatally. Mechanisms regulating this process are not well defined. However, studies of urogenital tract development in murine systems, particularly those involving tissue recombination and targeted gene mutation, indicate that the ideal uterine organizational programme evolves epigenetically through dynamic cell–cell and cell–matrix interactions that define the microenvironmental conte...

Development in vitro is influenced by embryo density, serum, somatic cell co-culture and the production of 'embryotrophic' paracrine and autocrine factors. Research in our laboratory has focussed principally on the insulin-like growth factor (IGF) family We have demonstrated that pre-attachment bovine and ovine embryos express mRNAs encoding a number of growth factor ligand and receptor genes including all members of the IGF ligand and receptor family througho...

During early pregnancy the bovine embryo must produce a protein called interferon τ which inhibits the development of the luteolytic mechanism. Failure to inhibit luteolysis is the major cause of pregnancy loss in cows. The embryo must produce sufficient quantities of interferon τ by about day 16 to prevent luteolysis. Its ability to achieve this is largely dependent on the pattern of maternal progesterone production. A late rise in progesterone after ovulation or po...

Early pregnancy is maintained in ruminants through the actions of conceptus-derived interferon (IFN)-tau on the endometrium. IFN-tau alters uterine release of PGF2α, which results in rescue of the corpus luteum and continued release of progesterone. The mechanism of action of IFN-tau includes inhibition of oestradiol receptors, consequent reduction in oxytocin receptors, activation of a cyclooxygenase inhibitor, and a shift in the PGs to favour PGE2 ...