Regulation of the Catecholamine .BETA.-Adrenergic System in Ventricular Remodeling of Hypertension

Abstract

Differences in structural remodeling are believed to be influenced by hormonal systems in hypertension. The objective of the present study was to investigate the change in the circulating catecholamine beta-adrenergic system in the left ventricle remodeling process in hypertensives. One hundred and thirty-four men (mean age, 53 years) had essential hypertension and underwent echocardiography before treatment. Normal morphology (n = 26) and concentric remodeling (n = 41) were defined by a relative wall thickness at diastole (RWT) of < 0.44 and > or = 0.44, respectively, and concentric hypertrophy (n = 28) and eccentric hypertrophy (n = 39) by a left ventricular mass index (LVMI) of < 150 g/m(2) and > or = 150 g/m(2), respectively. Forty healthy males were studied as normal controls. Plasma levels of norepinephrine (NE) and epinephrine (E) were measured by high performance liquid chromatography. The density of lymphocyte beta-adrenoceptors (beta-AR) and the content of intralymphocyte cyclic AMP (cAMP) in peripheral blood were measured using (3)H-dihydroalpneol as a ligand and protein binding assay, respectively. The plasma levels of NE and E in the 4 groups of patients with essential hypertension were significantly increased compared with the control group. The density of lymphocyte beta-AR and the content of intralymphocyte cAMP of peripheral blood in the normal morphology, concentric remodeling, and concentric hypertrophy groups were significantly higher than those in the control group, while the values in the eccentric hypertrophy group were significantly lower than those in the control group. Among the 4 groups, the plasma levels of NE and E had increased the most in the normal morphology group, followed in decreasing order by the concentric remodeling, concentric hypertrophy, and eccentric hypertrophy groups; the density of lymphocyte beta-AR and the content of intralymphocyte cAMP of peripheral blood in the normal morphology, concentric remodeling, and concentric hypertrophy groups increased while they decreased in the eccentric hypertrophy group in patients with essential hypertension. The catecholamine beta-adrenergic system appears to be related to left ventricular remodeling of hypertension. In this process, catecholamines increased continually. The density of beta-AR and the content of cAMP in peripheral lymphocytes increased at first and then decreased.