GC MS ANALYSIS OF URINARY-EXCRETION OF 9-ALPHA,11-BETA-PGF(2) IN ACUTE AND EXERCISE-INDUCED ASTHMA IN CHILDREN/

Background 9 alpha,11 beta-Prostaglandin (PG) F-2 is an initial metabo lite of PGD(2) which has a potent bronchoconstrictive activity. Object ives We measured the urinary levels of 9 alpha,11 beta-PGF(2) in asthm atic children to investigate its role in not only acute asthmatic atta ck in a time course study but also in exercise-induced asthma (EIA). M ethods In the acute asthma study, 30 asthmatic children were examined. Urine samples were collected on the first, third, and sixth days. Uri nary levels of 9 alpha,11 beta-PGF(2) were measured with gas chromatog raphy mass spectrometry using the electron impact method. In the exerc ise challenge study, 14 children with ELA and 14 children without EIA were studied. Urine samples were collected before exercise challenge, and at 1 h, and 5 h after exercise challenge. Urinary levels of 9 alph a,11 beta-PGF(2) were measured. Results Elevated urinary levels of 9 a lpha,11 beta-PGF(2), which were observed on the first day when treatme nt was started in the hospital, were gradually decreased on the third day (P < 0.05), and on the sixth day (P < 0.01). A significant correla tion between urinary levels of 9 alpha,11 beta-PGF(2) and symptom scor es (P < 0.005) was observed on the first day. In EIA, there was a sign ificant increase in urinary levels of 9 alpha,11 beta-PGF(2) at 1 h (P < 0.01) and at 5 h (P < 0.01) after exercise challenge, but not in th e children without EIA. Conclusion 9 alpha,11 beta-PGF(2) may be invol ved in the pathogenesis of acute and exercise-induced asthma in childr en.