Induction of fatty acid cyclooxygenase in rat aortic smooth muscle cells by estradiol

We have previously reported that estradiol stimulates prostacyclin biosynthesis in cultured rat aortic smooth muscle cells by increasing fatty acid cyclooxygenase activity, and induction of new protein biosynthesis is involved since the effect of estradiol is blocked by cycloheximide treatment. In order to see whether estradiol stimulates de novo biosynthesis of fatty acid cyclooxygenase in cells, a specific radioimmunoassay of fatty acid cyclooxygenase was used to measure the enzyme. Estradiol significantly increased immunoreactive fatty acid cyclooxygenase in cells. Consequently, increase in cyclooxygenase activity results in the production of more prostaglandin endoperoxides for final increased synthesis of prostacyclin in these cells.