Anti-allergic activity of formoterol, a new beta-adrenoceptor stimulant, and salbutamol in human leukocytes and human lung tissue.

Formoterol and salbutamol were compared for in vitro inhibition of allergen-induced histamine release from allergic leukocytes and human lung tissue passively sensitized with allergic serum. Formoterol inhibited the release of histamine from leukocytes but salbutamol showed little inhibiting effect. When combined with theophylline, formoterol was a more potent inhibitor of the release of histamine from leukocytes in allergic patients than salbutamol. In fragments of human lung sensitized with allergic serum, the concentration required to inhibit histamine release by 50% was 2 x 10(-11) M for formoterol and 8.5 x 10(-9) M for salbutamol. The potency of salbutamol and formoterol in blocking specific 3H-dihydroalprenolol binding to beta-adrenoceptors on guinea pig lung membranes revealed that formoterol had higher affinity for beta-adrenoceptors than salbutamol, and the concentration required for half-maximum stimulation of adenylate cyclase was approximately 200-fold higher for salbutamol than for formoterol.