title: Trophoblastic factors and the maternal recognition of pregnancy in sheep and cattle.
abstract: The establishment of pregnancy in domestic ruminants depends upon the continued secretion of progesterone by the corpora lutea. In non-pregnant cycles the corpora lutea regress between days 12-15 after oestrus in the sheep; this process must be blocked to ensure continued exposure of the uterus to progesterone. This review discusses the evidence that embryonic products are involved in the maintenance of corpus luteum function, the identification of factors which may be responsible for this maintenance and the probable mechanism of action. The discussion centres on the recent identification of a trophoblast interferon which is thought to be the major trophoblastic factor preventing luteolysis in sheep and cattle.
authors.affiliation: AFRC Research Group on Hormones & Farm Animal Reproduction, Institute of Animal Physiology & Genetics Research, Babraham.
authors.forename: H J
authors.initials: HJ
authors.lastname: Stewart
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002417:Cattle; D003340:Corpus Luteum Maintenance / Q000502:physiology*; D015237:Dinoprost / Q000031:analogs & derivatives / Q000097:blood; D005260:Female; D007370:Interferon Type I; D008186:Luteolytic Agents / Q000037:antagonists & inhibitors; D008969:Molecular Sequence Data; D010121:Oxytocin / Q000502:physiology; D010972:Platelet Activating Factor / Q000502:physiology; D011247:Pregnancy; D011257:Pregnancy Proteins / Q000235:genetics / Q000502:physiology; D011270:Pregnancy, Animal / Q000502:physiology*; D011374:Progesterone / Q000378:metabolism; D012689:Sequence Homology, Nucleic Acid; D012756:Sheep; D014327:Trophoblasts / Q000502:physiology*
chemical_list: D007370:Interferon Type I; D008186:Luteolytic Agents; D010972:Platelet Activating Factor; D011257:Pregnancy Proteins; C020947:interferon tau; C008228:15-keto-13,14-dihydroprostaglandin F2alpha; D011374:Progesterone; D010121:Oxytocin; D015237:Dinoprost