Inhibitory effect of estrogen on vascular contraction from male rats of different ages.

ABSTRACT

Both age and sex influence vascular contractile functions and play significant roles in cardiovascular regulation. Recent research has focused on the action of sex steroids on blood vessels and characterized both endothelium-dependent as well as-independent effects in agonists-induced contractile response. However, to study the combined influences of age and sex steroids present a complicated situation. In the current investigation, we studied the role of both these physiological factors in an in vitro approach. We found that high concentrations of estrogen (E2, 17 beta-estradiol) significantly inhibited contractile response induced by KCI in endothelium-denuded aorta derived from both young (24 wk) and aged (53 wk) male rats. The contractile responses in aorta from aged rats were significantly less than that from young adults in the absence or presence of E2 indicating that the vascular effect of E2 could be demonstrated in both young and aged male rats. Taken together, our data suggest that E2's action on endothelium-independent, KCI-induced contractile response in vitro could serve as a simple model system to examine the interaction of aging process and gender difference on vascular functions.