Sexual dimorphism in blood pressure response to thromboxane agonist U 46619 and to endothelin.

The blood pressure rising effect of two vasconstrictoryacting substances (the thromboxan agonist U 46619 and the endothelium-derived peptide endothelin-1) differs in male and in female rats and this fact depends on normotensive or hypertensive levels of blood pressure. Whereas in male rats the drug effect was changed by pretreatment with aspirin, in female rats aspirin was uneffective in changing the blood pressure response to the agents. It could be suggested that the mechanism(s) for blood pressure regulation, especially the vasoconstrictor system, is different in males and females.