Aspects of prostaglandin action in asthma

Eight patients with type I allergic bronchial asthma were given specific allergens by inhalation until symptoms and signs of asthma attacks were provoked. In some of these patients the provocation was repeated with premediciation of heparin, theofyllamin, small doses of cortisone (beclomethasone inhalations) or pretreatment within indomethacin. Before and after the provocation as in the three patients with exercise-induced asthma, peripheral venous blood sampled and analyzed for 15-keto-13,14-dihydro-PGF2alpha using combined gas--liquid chromatography-mass spectrometry. The allergen or exercise-provoked asthmatic attacks were associated with an up to eightfold increase in 15-keto-13,14-dihydro-PGF2alpha, the main metabolite of PGF2alpha in plasma. The increase in PGF2alpha metabolite which could be demonstrated within a few minutes after starting the provocation or finishing the exercise test seemed to be correlated to the severity of the attack in the allergic asthma but not clearly in exercise asthma. Pretreatment with different drugs did not give significant change in allergen sensitivity or plasma metabolite of PGF2alpha, except after pretreatment with indomethacin where one patient showed a fairly unchanged allergen sensitivity but a marked decrease in the plasma level of the PGF2alpha metabolite. The role of prostaglandins, their precursers and intermediates in prostaglandin synthesis, in the pathogenesis of asthma is indeed complex.