Testosterone modulates endothelial function in hypertensive rats
Cardiovascular disease is a major cause of death worldwide. Testosterone is associated with development of hypertension, a risk factor for cardiovascular disease, due to the greater incidence in men and postmenopausal women. However, recent studies suggest that testosterone may have protective effects in some contexts.
Arapa-Diaz et al. assessed whether testosterone could affect endothelium- dependent coronary vascular reactivity in spontaneously hypertensive rats. Male rats were divided into four groups: sham, orchidectomised (ORX), ORX with replacement testosterone (ORX+T) or ORX with testosterone plus aromatase inhibitor (ORX+T+AI). Drug treatments were for 15 days.
Systolic and diastolic blood pressure increased over time in sham, ORX+T and ORX+T+AI groups but not in ORX alone, consistent with depletion of endogenous testosterone inhibiting development of hypertension. Aromatase inhibition did not have an independent effect, precluding a role for oestrogens. Using a modified Langendorff perfusion method, the authors assessed coronary vascular bed function. While coronary perfusion pressure was unchanged in all groups, testosterone treatment increased bradykinin-induced vasodilation in ORX rats.
Although testosterone did not reduce blood pressure, it modulated endothelial function and promoted relaxation in the coronary vascular bed. These results suggest that testosterone can have regional effects in the cardiovascular system under hypertensive conditions.
Read the full article in Journal of Molecular Endocrinology 65 125–134