Stability of leukotrienes C4 and D4 in human urine

The ex vivo stability of leukotrienes (LT) C4 and D4 in human urine was tested in an experimental model. The various LTs were identified/measured by HPLC, liquid scintillation counting, RIA, UV-absorbance and GC-MS. If fresh urine was incubated under physiological conditions added LTC4 was converted in a time-dependent manner to LTD4 (t1/2 about 0.5 h) and to LTE4 (t1/2 about 6 h), respectively. At the end of the 22 h incubation period less than 10% of the initial LTC4 was detectable. LTB4 was stable under these conditions. Therefore the enzymatic urinary metabolism of LTs should be considered in experimental and clinical studies when urine is collected under different conditions.