[The changes in beta-adrenergic receptors and cyclic AMP levels of lymphocytes in patients with COPD]

The maximal binding capacity (Bmax) of beta-adrenergic receptors and the production of intracellular cAMP in response to isoproterenol in peripheral blood lymphocytes were measured by radioligand binding assay and competitive protein-binding method respectively. Two groups of COPD patients (19 cases was at the onset of disease, 17 cases was stable) were investigated and 20 normal subjects as control. The amount of Bmax at the onset of COPD (208.55 +/- 14.14fmol/10(8)cells) and during the stable stage (299.25 +/- 13.90fmol/10(6)cells) was significantly lower than that in normal subjects (338.35 +/- 12.22fmol/10(8)cells) (P less than 0.01). There were also obvious differences in amounts of Bmax between two groups of COPD (P less than 0.01). The changes of intracellular cAMP were similar to the results of Bmax. This study indicated that beta-adrenergic receptor function is attenuated in COPD patients especially at the onset of the disease. The possible mechanism of the reduction of beta-adrenergic receptor and the clinical significance in the use of beta-adrenoceptor agonist were discussed.