Detection of sputum eicosanoids in cystic fibrosis and in normal saliva by bioassay and radioimmunoassay

We have measured arachidonic acid (AA) metabolites, leukotrienes (LTs) and prostanoids (Ps), in sputum of patients with cystic fibrosis (CF) and in normal saliva using bioassay and radioimmunoassay (RIA). Almost three times as much LTB4 is present in CF extracts compared with slow reacting substances (SRSs). Leukotrienes were not detected in normal saliva. In CF sputum there is a three‐fold increase in the level of the vasodilator prostanoid prostaglandin E2 (PGE2) and the stable metabolite of prostacyclin, 6‐oxo PGF1 alpha compared with the vasoconstrictor prostaglandin F2 alpha (PGF2 alpha) and thromboxane B2 (TxB2), a hydrolysis product of thromboxane A2. Experiments with BW755c (25 micrograms ml‐1, n = 3) indicated that the majority of this activity was not produced during the extraction procedure. The detection of LTs and Ps in sputum of CF patients shows that these substances are present at biologically active concentrations and may contribute to the pathophysiology of this disease.