Placental synthesis of estrogens at parturition and during placental retention in the cow

S. Pimentel, G. Evans, W. C. Wagner

Research output: Contribution to journalArticlepeer-review


Nine cows were submitted to lutectomy at 250 or 270 d of pregnancy and catheters were implanted in the jugular, carotid, uterine artery and uterine vein to determine endocrine changes following lutectomy and throughout parturition. Blood samples were collected at 8-h intervals and assayed for estrogens. Fetal and maternal placental tissues were also collected at parturition and 3 d postpartum for incubation studies on estrogen synthesis. Based on plasma concentrations, the uterus is able to secrete considerable quantities of unconjugated and conjugated estrone (E1) and estradiol 17 μ (E2α) at both 250 and 270 d of gestation. In vitro conversion of androstendione to total estrogens averaged 32.4% and 16.8% for fetal and maternal tissues at parturition, respectively. Incubation of placental tissues collected from animals with placental retention on Day 3 postpartum resulted in conversion of 3.2 and 4.6% of androstendione by fetal and maternal tissues, respectively. One cow which retained the placenta was sampled until 3 d postpartum and assay of the plasma estrogen content indicated that there was always a higher concentration of estrogen in the uterine vein than in the uterine artery, supporting the in vitro incubation data.

Original languageEnglish (US)
Pages (from-to)755-766
Number of pages12
Issue number6
StatePublished - Dec 1987


  • cattle
  • estrogens
  • parturition
  • retained placenta

ASJC Scopus subject areas

  • Small Animals
  • Food Animals
  • Animal Science and Zoology
  • Equine


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