901-116 Coronary Vascular Relaxation Induced by Testosterone In Vivo is Gender Independent

To assess coronary vasoreactive response of testosterone and its relation to gender, we examined the effect of intracoronary testosterone (10-10to 10-6M) on epicardial and resistance coronary arteries in vivo in both male (5) and female (5) dogs. Changes in average peak flow velocity (APV) were assessed using a 0.014” Doppler guidewire (Cardiometrics), and epicardial cross-sectional area (CSA) was measured using a 4.3F, 30MHz ultrasound imaging catheter (CVIS). Guidewire and imaging catheter were positioned in the left circumflex artery. Testosterone induced a significant increase in both CSA, APV and calculated volumetric coronary blood flow (CBFI at the 10-7and 10-6M concentrations (CSA: 15.2±10.2% increase at 10-6M (p=0.05); APV: 36.4±12.8 increase at 10-7(p<0,01) and 73.8±66.8% increase at 10-6M (p=0.004); CBF: 205% increase at 10-6M (p=0.04)). Coronary vasorelaxation was equal in both males and females. No significant changes in heart rate or systemic pressure were noted.ConclusionWe conclude that acute testosterone administration induces epicardial and resistance coronary artery dilation in vivo and coronary vasorelaxation is independent of gender