Effect of Drug Treatment and Aerosoled Antigen Sensitization on Cyclic AMP and β Adrenergic Receptors of Guinea Pig Lung

The interaction between the number of β adrenergic binding sites and the ability of a β adrenergic agonist, isoproterenol, to increase cyclic AMP content of guinea pig lung slices was studied. A complex relationship was found. Chronic sensitization of the guinea pig to an aerosol of ovalbumin resulted in lung slices which were hyporesponsive to isoproterenol in vitro, yet possessed an unchanged number of beta adrenergic binding sites. Chronic exposure of guinea pigs to aerosoled isoproterenol or acute treatment with hydrocortisone did not change the number of β adrenergic binding sites or the responsiveness of the tissue to isoproterenol in vitro. However, chronic hydrocortisone treatment increased the number of binding sites found on the lung slices by 44%, yet there was no change in the responsiveness of the tissue to isoproterenol in vitro. These data suggest that drugs and disease may change the relationship between the various components of the β adrenergic binding - adenylate cyclase complex of lung.