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pubmed:abstractText |
The present study was undertaken to determine whether phospholipase D participates in the mitogenic action of arginine vasopressin (AVP) in cultured rat glomerular mesangial cells. AVP promptly increased the phosphatidylethanol formation in a concentration-dependent manner, which indicates the activation of phospholipase D. When cells were preincubated with 2,3-diphosphoglycerate or carbobenzyloxy-leucine-tyrosine-chloromethylketone (zLYCK), inhibitors of phospholipase D, the 1 x 10(-7) M AVP-produced phosphatidylethanol was significantly attenuated. Also, inhibitors of protein kinase C, staurosporine and calphostin C, reduced the AVP-induced increase in phosphatidylethanol. AVP activated mitogen-activated protein (MAP) kinase in a concentration-dependent manner. Such an activation was significantly reduced by 2,3-diphosphoglycerate, zLYCK, or staurosporine. Also, AVP stimulated [3H]thymidine incorporation, an effect significantly less in the presence of 2,3-diphosphoglycerate or zLYCK. Similar results were obtained with exogenous bacterial phospholipase D. Both MAP kinase and [3H]thymidine incorporation were not altered by 2,3-diphosphoglycerate or zLYCK per se. These results indicate that AVP activates phospholipase D and promotes cellular growth mediated through phospholipase D, in addition to a phospholipase C-dependent signal transduction, in glomerular mesangial cells.
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