Greater β‐Adrenergic Receptor Mediated Vasodilation in Women Using Oral Contraceptives

Abstract

Premenopausal women exhibit greater peripheral β‐adrenergic receptor (β‐AR) mediated vasodilation when compared to postmenopausal women, suggesting changes in female sex hormones may alter neurovascular control. Oral contraceptive use modulates cyclic hormonal profiles and therefore may influence β‐AR mediated vasodilation. We hypothesized β‐AR mediated vasodilation is greater in young (24±1 yrs), healthy women using oral contraceptives (OC+, n=13) compared to those not using oral contraceptives (OC−, n=12). Forearm blood flow (FBF) was measured by Doppler ultrasound during graded brachial artery infusion of the β‐AR agonist, isoproterenol (ISO: 1, 3, 6, and 12 ng/100g lean tissue/min). Forearm vascular conductance was calculated (FVC = FBF/MAP, ml/min/100mmHg), and the rise in FVC during ISO infusion (DFVC; FVCinfusion − FVCbaseline) was used to quantify β‐AR mediated vasodilation. Women were studied during the early follicular phase of the menstrual cycle (days 1–5) or low hormone phase of oral contraceptive use. ISO increased FVC in both groups (p<0.001). In support of our hypothesis, ISO mediated ΔFVC was greater in OC+ compared to OC− (main effect of group, p=0.020). Expressing data as FVC, FBF, and ΔFBF resulted in similar conclusions. These data are the first to demonstrate greater β‐AR mediated vasodilation in OC+ compared to OC−, and suggest altered hormonal profiles associated with oral contraceptive use may influence neurovascular control.Support or Funding InformationNIH R01 HL105820