5-HETE: uptake, distribution, and metabolism in MDCK cells

The interaction of (S)-5-hydroxy-6-trans-8,11,14-cis-eicosatetraenoic acid (5-HETE) with Madin-Darby canine kidney (MDCK) cells was investigated to determine whether this lipoxygenase product might influence tubular epithelial function. When incubated with arachidonic acid, MDCK cells failed to synthesize any 5-HETE. However, MDCK cells can take up 5-HETE to a much greater extent than either 12- or 15-HETE. 5-HETE uptake occurred from both the apical and basolateral surfaces and was not saturated at concentrations up to 10 microM. Much of the 5-HETE was incorporated into phospholipids, primarily phosphatidylcholine and phosphatidylethanolamine. After a 1-h incubation 5-HETE was found to be localized in either the microsomal and/or plasma membrane of MDCK cells. After pulse labeling for 1 h, MDCK cells released 35% of 5-HETE compared with 10% of the incorporated arachidonate during the next 24 h, indicating a much more rapid turnover of newly incorporated 5-HETE. When MDCK cells were incubated with 5.0 microM 5-HETE, their capacity to produce prostaglandin E2 was reduced greater than 50% in as little as 5.0 min. Since 5-HETE enters epithelial phospholipids and reduces prostaglandin production, it apparently has the capacity to modulate renal function if it is released in the proximity of the tubular epithelium during inflammatory reactions.