Testosterone acts as a coronary vasodilator by a calcium antagonistic action

T acts as a vasodilator in vitro and in vivo. Supplemental T therapy in humans with angina improves symptoms and reduces objective measures of ischemia. In left anterior descending coronary arteries taken from adult male Wistar rats, T abolishes 100 4.2% of calcium-dependent contraction induced by potassium chloride, 82.3+/-6.1% of the mostly calcium-dependent contraction induced by prostagiandin-F-2-alpha, but only 45.3+/-3.4% of the contraction induced by phorbol-1 2,1 3-dibutyrate (PDBu) in the presence of extracellular calcium, and 54.5+/-4.5% of the contraction induced by PDBu in the absence of extracellular calcium. These findings suggest that T is primarily inhibiting the calcium-dependent elements of vascular contraction.