Acute regulation of lymphocyteβ-adrenoceptor activity in pheochromocytoma

Abstract

The effect of an acute endogeneous catecholamine stimulation on the regulation of lymphocyte beta-adrenoceptor activity was studied in a patient with pheochromocytoma. Baseline blood pressure, heart rate, adrenoceptor density, and plasma concentrations of epinephrine, norepinephrine, and cyclic adenosine monophosphate were normal. Excessive spontaneous increases of catecholamine concentrations were accompanied by a rise in blood pressure, bradycardia, and an acute up-regulation of beta-adrenoceptors. Plasma concentrations of cyclic adenosine monophosphate paralleled the increase in receptor density and blood pressure. After normalization of catecholamine plasma levels, blood pressure, and beta-adrenoceptor density returned to baseline values. This observation adds support to the theory that an acute catecholamine stimulation leads to an acute sensitization of the beta-adrenoceptor-adenylatecyclase-cyclic-adenosine-monophosphate system leading to blood pressure elevation.