Influence of Sex on the Reactivity to Endothlelin-1 and Noradrenaline in Spontaneously Hypertensive Rats

Abstract

The response to endothelin-1 and noradrenaline in isolated aortas in vitro and mesenteric arterioles in situ was studied in male and female spontaneously hypertensive rats (SHR). Greater sensitivity to endothelin-1 and noradrenaline and decreased reactivity to endothelin-1 but not to noradrenaline were found in aortas of male SHR. Mesenteric arterioles of male SHR were more sensitive to endothelin-1 and noradrenaline. Aortas and mesenteric arterioles of female SHR exhibited similar sensitivity to endothelin-1 as compared to controls, whereas a greater reactivity to this agent was only observed in microvessels. It is suggested that sex-linked alterations of vascular reactivity exist in SHR. These alterations seemed not to affect all vascular territories and were not due to differences in blood pressure levels of male and female SHR.

Key Words:

• SHR
• Endothelin-1
• Noradrenaline