epidermal-growth-factor and tetramethrin

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.

Topics: 3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester; Adenosine Diphosphate Ribose; Animals; Calcium; Cell Line; Cobalt; DNA Replication; Epidermal Growth Factor; GTP-Binding Proteins; Lanthanum; Mice; Mice, Inbred BALB C; Pertussis Toxin; Pyrethrins; Somatomedins; Time Factors; Virulence Factors, Bordetella