Measurement of plasma prostaglandins during exercise-induced bronchospasm

Bronchospasm following exercise is a phenomenon which occurs in most patients with reversible airway disease. The pathophysiologic mechanism leading to this bronchoconstriction with exercise has not yet been defined. Recently, prostaglandins have been implicated in the etiology of asthma. The purpose of this investigation was to determine changes in plasma prostaglandins occurring during exercise-induced asthma. Eight ambulant asthmatics were chosen for baseline pulmonary spirometry and peripheral venous blood prostaglandin E and F levels. The asthmatics were then exercised to 80% of their age-predicted maximal heart rate via a multistage branching treadmill protocol. At 5, 15, and 30 min following exercise, pulmonary spirometry was again performed and peripheral venous blood collected at the indicated times. Clinical bronchospasm as characterised by audible wheezing and >15% decrease in FEV₁ and MMEFR was obtained in all of the asthmatics. Peripheral PGE and PGF_2α determinations following this exercise protocol were not altered significantly: (PGE: 0 mm, 238; 5 min, 185; 15 min, 248; 30 min, 256 pg/ml); (PGF_2α: 0 min, 50; 5 min, 24; 15 min, 25; 30 min, 17 pg/ml) (p > 0.1). In summary, no significant change in peripheral blood prostaglandin E and F_2α levels as determined by radioimmunoassay was noted at the time of exercise-induced bronchospasm.