Differential effect of dexamethasone on the regulation of phospholipase A2 and prostanoid synthesis in undifferentiated and phorbolester-differentiated U937 cells |
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Authors: | L Koehler R Hass M Goppelt-Struebe V Kaever K Resch |
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Institution: | Department of Pharmacology, Medical School of Hannover, Federal Republic of Germany. |
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Abstract: | The human undifferentiated histiocytic cell-line U937 can be induced to differentiate by incubation with 12-0-tetradecanoylphorbol-13-acetate (TPA) into macrophage-like cells. Dexamethasone reduced the prostaglandin production in TPA-differentiated U937 cells dose dependently, whereas undifferentiated U937 cells were dexamethasone insensitive. Concomitantly phospholipase A2, the enzyme liberating the prostaglandin precursor arachidonic acid, was inhibited by dexamethasone in TPA-differentiated but not in undifferentiated U937 cells. The activity of lysophosphatide acyltransferase, the key enzyme of fatty acid reacylation into phospholipids, remained unchanged both in undifferentiated and TPA-differentiated U937 cells. The data suggest that responsiveness to glucocorticoid-dependent regulation of prostanoid synthesis is acquired by cells of the monocyte-macrophage lineage late in differentiation. |
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Keywords: | U937 cell line differentiation prostaglandins |
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