Inositol lipid metabolism in vasopressin stimulated hepatocytes from rats infused with tumor necrosis factor |
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Authors: | J A Spitzer E B Rodriguez de Turco |
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Institution: | Department of Physiology, Louisiana State University Medical Center, New Orleans 70112. |
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Abstract: | We studied the effect of i.v. infusion of human recombinant tumor necrosis factor alpha (rHuTNF alpha, Cetus, 15 micrograms/100 g bw over 3 h) on vasopressin (VP)-stimulated 32P-inositol lipid turnover and the release of 3H-inositol phosphates in isolated rat hepatocytes. The early VP-induced decrease (within 30 s) in 32P-phosphatidylinositol 4-phosphate and 32P-phosphatidylinositol 4,5-bisphosphate labeling was significantly reduced (-40%) and at the same time the uptake of 32P into phosphatidic acid was 50% lower than in saline-infused (matched control) rats. Within 5 min of VP-stimulation, lower 32P phosphatidylinositol (-40%) and higher 32P-phosphatidic acid (+30%) labeling were observed in rHuTNF alpha-infused rats. Infusion of rHuTNF alpha also affected the VP-induced release of 3H-inositol phosphates. The accumulation of 3H-inositol-labeled water soluble products was decreased by 25% and 17% at 30 s and 10 min, respectively. These data show that rHuTNF alpha mimics early perturbations induced by Escherichia coli endotoxin infusion in VP-stimulated inositol lipid metabolism in rat hepatocytes. |
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