AJP - Cell Physiology, Vol 256, Issue 1 C1-10, Copyright © 1989 by American Physiological Society
5-HETE: uptake, distribution, and metabolism in MDCK cells
J. A. Gordon, P. H. Figard, G. E. Quinby and A. A. Spector
Department of Internal Medicine, University of Iowa College of Medicine, Iowa City 52242.
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.
