Gender differences in venous endotheliumdependent responses to aggregating platelets

Much of the current research on gender differences in vascular function has focused on coronary arterial disease. However, there are also clinically manifested differences in venous disease. This study examined gender differences in responses of veins to platelets and platelet-derived products. Femoral veins from sexually mature, gonadally intact male and female pigs were cut into rings and suspended in organ chambers for measurement of isometric tension. In some rings the endothelium was deliberately removed. Rings with endothelium from male pigs were more sensitive to the contractile effects of serotonin compared to females. Contractions were not altered by indomethacin or L-NMMA. There were no differences in relaxations to adenosine-5-diphosphate in rings with or without endothelium between veins from male and female pits Production of serotonin was similar in activated platelets from males compared to females; however, production of thromboxane B₂ was greater in platelets from males. These results identify gender differences in responses of veins to substances released from aggregating platelets and in secretion of substances from the activated platelets.