Measurement of β‐Adrenergic Receptors on Lymphocytes in Normal Subjects and Asthmatics in Relation to β‐Adrenergic Hyperglycaemic Response and Bronchial Responsiveness

Abstract

The numbers of .beta.-adrenergic receptors on lymphocytes in normal subjects and asthmatic patients were measured by the use of [125I]hydroxybenzylpindolol. Tbe numbers of .beta.-adrenergic receptors per lymphocyte in normal subjects, drug-free asthmatics and patients taking .beta.-stimulants were 1146 .+-. 98, 845 .+-. 14 and 582 .+-. 47 sites/cell (mean .+-. SE), respectively. The differences were statistically significant (P < 0.05) among these groups, while no statistically signficant differences were found in dissociation constants. A 42% decrease in the number of .beta.-adrenergic receptors per lymphocyte after administration of 6 mg/day of terbutaline for 7 days was noted in 4 volunteers. There was significant correlation (r = 0.68, P < 0.01) between the number of .beta.-adrenergic receptors per lymphocyte and the percentage increase in blood sugar 20 min after s.c. injection of 4 .mu.g/kg epinephrine. There was also significant correlation (r = 0.78, P < 0.005) between the number of .beta.-adrenergic receptors per lymphocyte and the respiratory threshold for acetylcholine. .beta.-Blockade and bronchial hypersensitivity in asthmatic patients may in part be due to a decreased number of .beta.-adrenergic receptors.