Cyclic nucleotide phosphodiesterase activity in patients with obstructive airways disease

Cyclic nucleotide phosphodiesterase activity was examined in the pulmonary tissues of patients with no obstructive airways disease, obstructive airways disease responsive to isoproterenol (responders) and obstructive airways disease non-responsive to isoproterenol (non-responders). The phosphodiesterase catalyzed hydrolysis of 0.45 microM levels of adenosine 3',5'-cyclic monophosphate (cAMP) and guanosine 3',5'-cyclic monophosphate (cGMP) was essentially the same in responders as in patients without disease, but was reduced in the non-responders. The results suggest that neither the postulated beta adrenergic receptor-cAMP system defect nor the depressed levels of cAMP reported in patients with bronchodilator-responsive obstruction is caused by an alteration of phosphodiesterase activity.