For both aims, the protocol design will be placebo-controlled and double-blind. For the second aim, only fluticasone pretreatment will be possible because the salmeterol component of the fluticasone/salmeterol combination preparation could influence albuterol responsiveness irrespective of any glucocorticoid effect. The timing of the endothelial function measurements in the long-term glucocorticoid/long-acting beta-agonist protocol and single dose ICS protocol is based on the past experience with ICS on airway vascular function. Single dose effects were seen within 15-30 min and waned by 90 min (25,26), while long-term treatment effects were no longer seen 3 weeks after ICS withdrawal (16).