Testosterone regulation of platelet and vascular thromboxane A2 receptors

Testosterone has been implicated as a risk factor for cardiovascular diseases and thromboxane A2 (TXA2) plays a role in these diseases. We tested the notion that testosterone regulates the expression of TXA2 receptors in platelets and vascular smooth muscle. Testosterone significantly increased the density of TXA2 receptors in cultured rat aortic smooth muscle and human erythroleukemia cells, a megakaryocyte-like cell. Treatment of rats with testosterone resulted in a significant increase in platelet and aortic TXA2 receptor density and increased responsiveness to TXA2 mimetics. We conclude that testosterone regulates the expression of TXA2 receptors.