Inhibition of Prostacyclin and Platelet Thromboxane A₂ by Aspirin

To the Editor: In the January 8th issue Preston et al.¹ describe the sustained inhibition of prostacyclin synthesis by vein segments after low-dose aspirin ingestion in five volunteers. In contrast to this report, we recently reported² on the failure of aspirin at doses of up to 20 mg per kilogram of body weight to reduce the production of prostacyclin by rat aortic slices. In the same study, we also noted inhibition of platelet prostaglandin production by aspirin with as little as 5 mg per kilogram. The discrepancy between our results and those of Preston et al. may be due to. . .