Simultaneous measurements of prostacyclin and thromboxane metabolites during the menstrual cycle

The balance between prostacyclin and thromboxane is known to be important for reproductive and cardiovascular health but has been difficult to quantify. Whereas their stable urinary metabolites, 6-keto-prostaglandin F1 alpha and thromboxane B2, may reflect in part systemic changes, it has been suggested that 2,3-dinor-6-keto-prostaglandin F1 alpha and 11-dehydro-thromboxane B2 more adequately reflect systemic production. Therefore we report for the first time the simultaneous measurements of 6-keto-prostaglandin F1 alpha, thromboxane B2, 2,3-dinor-6-keto-prostaglandin F1 alpha, and 11-dehydro-thromboxane B2 during the menstrual cycle. Timed urine collections were obtained from 18 ovulatory women, aged 22 to 40, during the midfollicular and midluteal phases. Serum estradiol, progesterone, urinary pregnanediol glucuronide, estrone glucuronide, and creatinine also were measured. Prostanoid extraction from urine by C18 and silica Bond Elut columns were then separated by high-performance liquid chromatography before radioimmunoassay. Concentrations of all urinary prostanoids were not significantly different in the follicular phase when compared with the luteal phase. A positive correlation of borderline significance was noted between luteal thromboxane B2 and pregnanediol glucuronide (r = 0.70) and between luteal estrone glucuronide and 2,3-dinor-6-keto-prostaglandin F1 alpha (r = 0.68). A significant correlation was found between follicular estrone glucuronide and the 6-keto-prostaglandin F1 alpha/11-dehydro-thromboxane B2 ratio (r = 0.83, p less than 0.04). These novel normative data suggest an influence of sex steroids on prostacyclin and thromboxane metabolism.