Formation of prostacyclin and thromboxane in man as measured by the main urinary metabolites

Abstract

Excretion of 2,3-dinor-6-ketoprostaglandin F 1α and 2,3-dinorthromboxane B 2, the main urinary metabolites of prostacyclin and thromboxane, was evaluated by gas chromatography-mass spectroscopy and radioimmunoassay, respectively, at various conditions in man. In healthy young males excretion of 2,3-dinor-6-ketoprostaglandin F 1α was of little variability, whereas urinary 2,3-dinorthromboxane B 2 showed marked interindividual but moderate intraindividual variations. The ratio of urinary 2,3-dinorthromboxane B 2 to thromboxane B 2 in young males was about 15. Excretion of 2,3-dinor-6-ketoprostaglandin F 1α in women of reproductive age was higher (155 ± 23 ng/g creatinine, P < 0.005) than in postmenopausal women (97 ± 24 ng/g creatinine) and in men (78 ± 7.6 ng/g creatinine) and increased significantly during pregnancy (1st trimester 230 ± 50 ng/ g creatinine; 3rd trimester 522 ± 53 ng/g creatinine). Urinary 2,3-dinorthromboxane B 2 showed no gender differences and no directed change was observed during pregnancy. In neonates urinary 2,3-dinorthromboxane B 2 (6.328 ± 1.210 ng/g creatinine) was high in their 3rd day of life and decreased rapidly thereafter. This pattern paralleled the behavior of 6-ketoprostaglandin F 1α. In young male smokers and non-smokers excretion of 2,3-dinor-6-ketoprostaglandin F 1α was not significantly different, whereas urinary 2,3-dinorthromboxane B 2 was elevated in smokers (609 ± 61 versus 351 ± 41 ng/g creatinine, P < 0.001). Values are mean ± S.E.