title: Formation of inositol phosphates and calcium mobilization in Swiss 3T3 cells in response to prostaglandin F2 alpha.
abstract: Signal transduction in the mitogenic action of prostaglandin F2 alpha on Swiss 3T3 cells has been studied. Confluent and quiescent Swiss 3T3 cells prelabeled with myo-[2-3H]inositol were stimulated with PGF2 alpha for 15 min at 37 degrees C in the presence of 5 mM LiCl, and the amount of total [3H]inositol phosphates, a sum of inositol tris-, bis-, and mono-phosphates, accumulated in the cells was determined. Addition of PGF2 alpha to the cells at 0.2 to 10 microM induced a 1.7 to 2.4-fold increase in [3H]-inositol phosphates. The accumulation was dose-dependent. Since assay of the agonist-dependent accumulation of inositol phosphates in the presence of LiCl has been used as a sensitive method for identifying those receptors that are coupled to the hydrolysis of phosphatidylinositol 4,5-bisphosphate [PtdIns (4,5)P2], these results indicate that PGF2 alpha induces in Swiss 3T3 cells hydrolysis of inositol lipids by a phospholipase C. The receptor-stimulated hydrolysis of PtdIns(4,5)P2 is usually coupled with a rise in cytoplasmic free Ca2+ concentration ([Ca2+]i). The effect of PGF2 alpha on [Ca2+]i was studied in quin-2 loaded Swiss 3T3 cells. On addition of 0.1 microM and 1 microM PGF2 alpha, there was an immediate increase in quin-2 fluorescence by 16 to 19% indicating a 1.5 to 1.8-fold increase in [Ca2+]i. These results therefore indicate that PGF2 alpha at 0.1 to 1 microM induces in Swiss 3T3 cells the hydrolysis of inositol lipids and a rise in [Ca2+]i.
mesh_terms: D000634:Aminoquinolines; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002478:Cells, Cultured; D015237:Dinoprost; D011464:Epoprostenol / Q000494:pharmacology; D006868:Hydrolysis; D007295:Inositol Phosphates / Q000378:metabolism*; D051379:Mice; D019269:Phosphatidylinositol 4,5-Diphosphate; D010716:Phosphatidylinositols / Q000378:metabolism; D011453:Prostaglandins / Q000494:pharmacology; D011460:Prostaglandins F / Q000494:pharmacology*; D011956:Receptors, Cell Surface / Q000187:drug effects; D013403:Sugar Phosphates / Q000378:metabolism*; D013929:Thromboxane B2 / Q000494:pharmacology
chemical_list: D000634:Aminoquinolines; D007295:Inositol Phosphates; D019269:Phosphatidylinositol 4,5-Diphosphate; D010716:Phosphatidylinositols; D011453:Prostaglandins; D011460:Prostaglandins F; D011956:Receptors, Cell Surface; D013403:Sugar Phosphates; D013929:Thromboxane B2; D015237:Dinoprost; D011464:Epoprostenol; C035739:Quin2; D002118:Calcium