SEX-DIFFERENCES IN ENDOTHELIAL FUNCTION IN NORMAL AND HYPERCHOLESTEROLEMIC SUBJECTS

Acetylcholine stimulates endothelial synthesis of nitric oxide from L- arginine. To investigate the influence of sex on endothelial function, we measured vasodilator responses to brachial artery administration o f acetylcholine in hypercholesterolaemic and control men and women. Me an response to acetylcholine was impaired (55% of that in controls at 15 mu g/min) in hypercholesterolaemic men but not in hypercholesterola emic women. L-arginine normalised responses to acetylcholine in hyperc holesterolaemic men, but had similar effects in hypercholesterolaemic and control women. These results suggest that women are protected agai nst adverse effects of hypercholesterolaemia on the L-arginine/nitric- oxide pathway.