Plasma glucagon response during exercise-induced asthma

Plasma glucagon levels and peak expiratory flow rates (PEF) were determined before and after treadmill exercise test in 5 atopic patients with exercise-induced asthma (EIA) and in 10 non-atopic patients with EIA, and also in 14 controls without exercise-induced bronchoconstriction. In addition, changes in plasma glucagon were determined during an allergen-inhalation challenge test in 5 asthmatics. Plasma glucagon was determined by radioimmunoassay using antiserum and 125I-labelled glucagon. Plasma glucagon level of atopic asthmatics at rest was significantly lower (P less than 0.05) than in non-atopic EIA patients. In the atopic EIA patients the plasma glucagon level increased by 41 per cent 10 minutes after exercise, whereas in the nonatopic EIA patients it decreased by about 19 per cent. In the controls there were only insignificant exercise-induced changes in the plasma glucagon level. The exercise-induced changes of the plasma glucagon in the atopic EIA patients differed significantly from those in the non-atopic EIA patients (P less than 0.05). No change in plasma glucagon was observed in five asthmatics during inhalation challenge tests with a known positive allergen. The results suggest that the rise in glucagon is a defence mechanism against exercise-induced broncho-constriction.