In the reproductive age, it is well-known that males are more sensitive to cardiovascular ischemic disease than females. In our study, we investigated the role of heme-oxigenase synthase (HO), which produce endogenous vascular protective carbon monoxide, in the development of sexual dimorphism in rats. We found that HO synthase enzyme activity, and the expression its HO-1 and HO-2 isoenzyme were increased in female rat aorta and left heart ventricle compared to males. Moreover, under in vivo circumstances, we demonstrated that i) administration of vasopressin provoked an increased mean arterial blood pressure response in the male; ii) the female myocardium was less sensitive towards angina than the male; iii) both differences could be aggravated by the inhibition of HO synthase. Finally, under in vitro circumstances, it was shown that i) aorta rings were more susceptible towards vasoconstriction by vasopressin in males compared to females; ii) isolated heart perfusion decrease was higher in males; iii) HO inhibition aggravated vasoconstriction in both sexes. In conclusion, the increased HO activity and HO isoenzyme expression in females might play a role in the sexual dimorphism of cardiovascular ischemia susceptibility in the reproductive age.
Prague, Czech Republic
24 - 28 Apr 2010
European Society of Endocrinology