Beta-adrenergic receptor density and function in left ventricular hypertrophy in young essential hypertensives

A sympathetic overactivity has been reported in the early stages of essential hypertension and has been involved in the pathogenesis of left ventricular hypertrophy (LVH) in essential hypertension. The state of beta2-adrenergic receptors as related to the presence of this complication was investigated in a group of 15 essential hypertensive patients and compared to 10 normotensive control subjects. Left ventricular mass index was determined by bidimensional echocardiography. Plasma catecholamine levels were measured by a radioenzymatic assay. beta2-adrenoceptor density was measured in intact lymphocytes by radioligand binding assay, using the hydrophilic ligand CGP 12177. beta2- adrenoceptor function was assessed by measuring intracellular cAMP levels in isoproterenol-stimulated lymphocytes. Left ventricular mass index (P < 0.05), body mass index (P < 0.01), plasma noradrenaline levels (P < 0.05) and beta2-adrenoceptor density (P < 0.05) were higher in hypertensives than in controls. Left ventricular mass index correlated with body mass index both in normotensives and hypertensives, as well as with plasma noradrenaline levels only in normotensives. Left ventricular mass index also showed a positive correlation with mean arterial pressure and an inverse relationship with beta2-adrenoceptor density and response only in hypertensive patients. In conclusion, left ventricular hypertrophy in young essential hypertensives is associated to a reduced beta2-adrenoceptor density and function, probably as a compensating mechanism of the hypertrophied myocardiocyte secondary to the increased sympathetic outflow. Journal of Human Hypertension (2000) 14, 17-21.