Effects of 6-Keto-prostaglandin E 1 on Perinatal Pulmonary Vascular Resistance

Abstract

The effects of a biologically active metabolite of PGI₂, 6-keto-PGE₁, were evaluated in fetal goats and newborn lambs using an in situ, constant-flow, isolated lower left lobe preparation. Intrapulmonary injections of 6-keto-PGE₁ (0.074-4.41 μg/kg) produced dose-dependent decreases in pulmonary vascular resistance, mean systemic arterial pressure, and heart rate in fetal goats. Fetal systemic responses to 6-keto-PGE₁ were significantly less following left atrial injections than after intrapulmonary injections. Newborn lambs also responded to intrapulmonary infusions of 6-keto-PGE₁ (0.078-5.15 μg/kg-min) with dose-dependent reductions of pulmonary vascular resistance and systemic arterial pressure. A possible role for 6-keto-PGE₁ in the modulation of perinatal pulmonary vascular resistance is discussed.