15-HETE: selective incorporation into inositol phospholipids of MDCK cells.
The interaction of 15-hydroxyeicosatetraenoic acid (15-HETE) and cultured MDCK renal tubular epithelial cells was investigated to determine whether incorporation of this lipoxygenase product will affect polyphosphoinositide formation. MDCK cells were incubated with 1 microM [3H]-15-HETE for 15 to 120 minutes. Maximum uptake occurred between 15 and 30 minutes, and after 60 minutes, 70% of the incorporated 15-HETE was present in the phosphatidylinositol (PI) fraction. Some 15-HETE was also incorporated into phosphatidylinositol-4-monophosphate (PIP) and phosphatidylinositol-4,5-bisphosphate (PIP2). However, even though more 15-HETE than arachidonic acid was incorporated into PI, the fractional amount of 15-HETE present in the polyphosphoinositides was smaller than arachidonic acid. Therefore, although 15-HETE is selectively channeled into PI, conversion of PI species containing 15-HETE to PIP and PIP2 is relatively impaired. This suggests that either PI containing 15-HETE is a less effective substrate for phosphorylation, or PI containing arachidonic acid is a preferred substrate. MDCK cells converted 15-HETE to polar metabolites that were released into the extracellular fluid. This process may constitute a renal tubular mechanism for the clearance of 15-HETE and related lipoxygenase products.
Girton
R A
RA
Department of Internal Medicine, University of Iowa College of Medicine, Iowa City 52242.
Spector
A A
AA
Gordon
J A
JA
D000818:Animals; D016718:Arachidonic Acid / Q000378:metabolism; D002460:Cell Line; D002478:Cells, Cultured; D004285:Dogs; D004848:Epithelium / Q000378:metabolism; D006893:Hydroxyeicosatetraenoic Acids / Q000378:metabolism*; D007684:Kidney Tubules / Q000378:metabolism*; D019269:Phosphatidylinositol 4,5-Diphosphate; D018129:Phosphatidylinositol Phosphates / Q000378:metabolism*; D010716:Phosphatidylinositols / Q000378:metabolism*; D010741:Phospholipases A / Q000378:metabolism
D006893:Hydroxyeicosatetraenoic Acids; D019269:Phosphatidylinositol 4,5-Diphosphate; D018129:Phosphatidylinositol Phosphates; D010716:Phosphatidylinositols; C037178:phosphatidylinositol 4-phosphate; D016718:Arachidonic Acid; C025984:15-hydroxy-5,8,11,13-eicosatetraenoic acid; D010741:Phospholipases A