title: Insulin-like growth factor II stimulates calcium influx in competent BALB/c 3T3 cells primed with epidermal growth factor. Characteristics of calcium influx and involvement of GTP-binding protein.
abstract: The action of insulin-like growth factor II (IGF-II) on calcium influx was studied in BALB/c 3T3 cells. IGF-II did not affect calcium influx rate in either quiescent or platelet-derived growth factor-treated "competent" cells. In contrast, IGF-II induced an approximately 2-fold sustained increase in calcium influx rate in competent cells briefly primed with epidermal growth factor ("primed competent" cells). The IGF-II-stimulated calcium influx was dependent on extracellular calcium and was inhibited by lanthanum, cobalt, and tetramethlin but not by nitrendipine. The IGF-II-stimulated [3H]thymidine incorporation was also dependent on extracellular calcium and was inhibited by cobalt and tetramethlin. A pharmacological stimulation of calcium influx by BAYK8644 resulted in an increase in [3H]thymidine incorporation in primed competent cells but not in either quiescent or competent cells. Pretreatment of primed competent cells with pertussis toxin completely abolished subsequent action of IGF-II on both calcium influx and [3H]thymidine incorporation. Inhibitory actions of pertussis toxin correlated well with toxin-induced ADP-ribosylation of a 41-kDa protein. The binding of 125I-IGF-II to membrane fraction was inhibited by guanosine 5'-O-(thiotriphosphate), and this inhibition was reversed by pretreatment of the cell with pertussis toxin. These results suggest that IGF-II stimulates calcium influx in primed competent BALB/c 3T3 cells by a mechanism involving G protein and that calcium influx may be a message of IGF-II action on cell proliferation.
mesh_terms: D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester / Q000494:pharmacology; D000246:Adenosine Diphosphate Ribose / Q000378:metabolism; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002460:Cell Line; D003035:Cobalt / Q000494:pharmacology; D004261:DNA Replication; D004815:Epidermal Growth Factor / Q000494:pharmacology*; D019204:GTP-Binding Proteins / Q000378:metabolism*; D007811:Lanthanum / Q000494:pharmacology; D051379:Mice; D008807:Mice, Inbred BALB C; D037342:Pertussis Toxin; D011722:Pyrethrins / Q000494:pharmacology; D013002:Somatomedins / Q000494:pharmacology*; D013997:Time Factors; D010566:Virulence Factors, Bordetella / Q000494:pharmacology
chemical_list: D011722:Pyrethrins; D013002:Somatomedins; D010566:Virulence Factors, Bordetella; D000246:Adenosine Diphosphate Ribose; D003035:Cobalt; D004815:Epidermal Growth Factor; D007811:Lanthanum; D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester; D037342:Pertussis Toxin; D019204:GTP-Binding Proteins; D002118:Calcium; C009424:tetramethrin