Placental vascular responses to 6-keto-prostaglandin E1 in the near-term sheep

David B. Schwartz, Terrance M. Phernetton, Michael K. Stock, John H G Rankin

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Abstract

6-Keto-prostaglandin E1 (6-keto-PGE1) is a biologically active, stable metabolite of prostaglandin I2 (PGI2). It has vasoactive properties similar to those of PGI2 and it has been shown to decrease the resistance of the renal, mesenteric, and pulmonary vascular beds. PGI2 is synthesized by the pregnant uterus and is vasoactive in the ovine placenta. The effects of 6-keto-PGE1 on uterine and placental blood flow in pregnant ewes were determined for comparison with those of PGI2. Near-term ewes and their fetuses were chronically catheterized to permit the measurement of regional blood flow by the radioactive microsphere method. In six sheep a 5-minute maternal jugular infusion of 3.25 μg/kg/min of 6-keto-PGE1 decreased mean arterial blood pressure from 89 ± 4.8 to 63 ± 7.1 mm Hg. Uterine vascular resistance decreased from 0.55 ± 0.11 to 0.35 ± 0.05 peripheral resistance units (PRU), but maternal cotyledonary resistance increased from 0.19 ± 0.04 to 0.27 ± 0.03 PRU. In five sheep a fetal intravenous infusion of 18 μg/min of 6-keto-PGE1 decreased mean fetal blood pressure from 43 ± 2 to 29 ± 2 mm Hg. Cotyledonary vascular resistance increased from 0.30 ± 0.02 to 0.55 ± 0.09 PRU · kg-1. In these sheep there were no significant changes in maternal uterine, renal, or cotyledonary blood flows. These results indicate that 6-keto-PGE1 is similar to PGI2 in that it produces maternal cotyledonary vasoconstriction, hypotension, and vasodilation in other organs.

Original languageEnglish (US)
Pages (from-to)406-410
Number of pages5
JournalAmerican Journal of Obstetrics and Gynecology
Volume145
Issue number4
Publication statusPublished - Feb 15 1983
Externally publishedYes

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ASJC Scopus subject areas

  • Medicine(all)
  • Obstetrics and Gynecology

Cite this

Schwartz, D. B., Phernetton, T. M., Stock, M. K., & Rankin, J. H. G. (1983). Placental vascular responses to 6-keto-prostaglandin E1 in the near-term sheep. American Journal of Obstetrics and Gynecology, 145(4), 406-410.