A Comparison of Human Pulmonary Arterial and Venous Prostacyclin and Thromboxane Synthesis- Effect of a Thromboxane Synthase Inhibitor

Abstract

The amounts of 6-keto-prostaglandin F_1α (6-keto-PGF_1α) and thromboxane B₂ (TxB₂) produced by the endothelial surfaces of paired samples of human pulmonary arteries and veins, obtained from patients undergoing thoracic surgery, were measured. The amounts of 6-keto-PGF_1α and TxB₂ produced by arteries compared with veins were not different. However, both arteries and veins produced more 6-keto-PGF_lα than TxB₂, the ratio being approximately 7.5:1 for both. 6-keto-PGF_lα synthesis by arteries was significantly correlated with that produced by veins but the relative amounts of TxB₂ were not correlated. 6-keto-PGF_lα synthesis was correlated with TxB₂ synthesis for veins but not for arteries. 8 of the 12 arterial samples exhibited some degree of intimal fibrosis. Incubation with the thromboxane synthase inhibitor, dazoxiben, caused a significant inhibition of vascular TxB₂ synthesis and a significant increase in 6-keto-PGF_lα synthesis. In 3 of the 5 cases the increase in 6-keto-PGF_lα was too large to be explained by the fall in TxB₂.