| Abstract: | It has been postulated that the patient with atopic dermatitis has defective beta adrenergic receptor function. However, a more generalized defect is suggested by the observation that cyclic AMP generation is diminished in these patients following stimulation with both isoproterenol and PGE1. To determine the nature of this abnormality, we measured beta adrenergic receptor binding directly on polymorphonuclear leukocyte membranes using the radiolabeled beta adrenergic antagonist (-) [3H]dihydroalprenolol (DHA). DHA binding was studied in 6 mild and 9 moderate-to-severe atopic dermatitis patients, and 8 normal controls using a subsaturating concentration of DHA (0.5 nM) to estimate receptor affinity and a saturating concentration of DHA (30 mM) to determine the total number of receptors per cell. No significant differences (p greater than .05) were found in the total number of receptors per PMN between the control population (805 +/- 95) and the mild atopic dermatitis patients (745 +/- 91) or the moderate to severe group (621 +/- 79). In addition, no significant differences in receptor affinity were found among any of the 3 study groups. These findings suggest that beta receptor binding in atopic dermatitis is normal. Reduced cyclic AMP generation in atopic dermatitis PMN leukocytes would appear to be due to a defect distal to the beta adrenergic receptor itself. |
