Decreased in vitro production of 6-keto-prostaglandin F1α by uterine arteries from postmenopausal women

Cessation of ovarian function is associated with a marked increased in morbidity and mortality secondary to ischemic heart disease. Estrogen replacement has been shown to impart protection against ischemic heart disease. We hypothesized that estrogen may influence vascular production of vasodilators such as prostacyclin. To investigate this relationship we have measured the production of 6-keto-prostaglandin F1 alpha, and thromboxane B2 by superfused uterine arteries from pre- and postmenopausal women. Arterial specimens from healthy normotensive premenopausal (n = 5) and postmenopausal women (n = 5) were superfused for 5 hours. Production of 6-keto-prostaglandin F1 alpha reached steady state levels by 120 minutes and remained linear for the length of the experiment. Indomethacin (4 x 10(-5) mol/L) added at 120 minutes significantly decreased prostanoid production. In subsequent experiments, 17 beta-estradiol in concentrations of 10, 100, 1000 ng/ml was added to the superfusion media at 120 minutes. Total production of 6-keto-prostaglandin F1 alpha by premenopausal arteries superfused with neat media during the steady state interval (3 hours) was significantly greater than that of postmenopausal specimens (1.25 versus 0.27 ng/mg dry tissue, p less than 0.05). Thromboxane B2 levels were undetectable in spent media. However, the addition of 17 beta-estradiol did not alter production of 6-keto-prostaglandin F1 alpha. These data suggest that arterial production of prostacyclin is significantly decreased in uterine arteries from postmenopausal women, but in this in vitro model system estrogens did not affect vascular prostanoid production.