Characteristics of the uptake of cysteine-containing leukotrienes by isolated hepatocytes.
Leukotrienes were transported into rat hepatocytes by a temperature- and energy-dependent mechanism. The uptake was saturable with high- and low-affinity sites (Km values approx. 1 and 17 microM). Competition and kinetic experiments indicated that leukotrienes C4, D4 and E4 were transported by a common mechanism. The maximal velocity of transport was about 50% higher for leukotrienes D4 and E4 than for leukotriene C4. Leukotriene B4, glutathione disulfide, and the glutathione-S-conjugate of acetaminophen did not interfere with the transport of leukotriene C into hepatocytes. This suggests that the process is specific for cysteine-containing leukotrienes. It is likely that the transport mechanism described here participates in biliary excretion of leukotrienes. This route was previously found to be a major one for elimination of leukotriene C3 in mice and guinea-pigs.