Endothelium-dependent gender differences in the response of the XXXX aorta.

@entity172 @entity251 @entity455 @entity53 @entity3774 @entity35
Segments of @entity35 aortic arch were studied to determine the existence of sexual dimorphism. The influence of the endothelium in mediating gender differences in contractility (maximum tension, Tmax) and sensitivity (ED50) to @entity3774 was measured. This was done in both intact and denuded @entity455 preparations which were dissected from adult male and female @entity35 . Group I comprised untreated male and female @entity35 ; Groups II and III were treated with @entity251 (10 mg/kg i.m.) or @entity53 (2.5 mg/kg i.m.), respectively, on days 1, 3 and 6 and sacrificed on day 7. Intact @entity455 preparations from untreated females were significantly less sensitive (P less than .01) and less contractile (P less than .025) than those from the males. After the intimal surface of the aortic arch rings was rubbed the rings from females exhibited a significant increase in Tmax. However, in vessels from males endothelial denudation had no effect on either Tmax or ED50. @entity251 treatment of female @entity35 significantly increased Tmax (P less than .01) and decreased the ED50 (P less than .01) when compared to rings from untreated females. @entity251 treatment did not significantly affect either parameter in vessels from females which had been rubbed. @entity251 treatment also had no significant effect in either intact or rubbed vessels from males. @entity172 treatment significantly increased the Tmax (P less than .05) of intact vessels from females and had no effect on other vessel segments. Thus, the gender difference in Tmax may relate to an attenuating effect of the endothelium on contractility in the rings from females.(ABSTRACT TRUNCATED AT 250 WORDS)
