Sexual dimorphism in aortic endothelial function of Zucker diabetic fatty rats: possible involvement of superoxide production (1051.8)

Little is known about the interaction between diabetes and sex in vasculature. This study was designed to investigate whether there were sex differences in rat aortic endothelium-dependent vasodilation (EDV) in Zucker diabetic fatty (ZDF) rats, and the potential role of superoxide. EDV to acetylcholine (ACh) was measured in aortic rings pre-contracted with phenylephrine before and after pretreatment with apocynin (100 μM), a NADPH oxidase (Nox) inhibitor. In addition, the level of Nox (a potent source of superoxide) and PKCβ mRNA expression were determined using real-time RT-PCR. ACh-induced relaxations were significantly greater in female lean rats compared with male lean rats. Accordingly, male lean rats had higher PKCβI expression level than female lean rats. Diabetes significantly impaired EDV in aortic rings from female ZDF rats, however, potentiated the relaxation in males. Pre-incubation of aortic rings with apocynin increased EDV only in diabetic female group, suggesting impairment of EDV in femal...