title: Ca2+-mobilizing actions of platelet-derived growth factor differ from those of bombesin and vasopressin in Swiss 3T3 mouse cells.
abstract: Addition of the mitogenic peptides bombesin and vasopressin to quiescent Swiss 3T3 mouse cells increased the cytosolic Ca2+ concentration without any measurable delay. In contrast, there was a significant lag period (16 +/- 1.2 s) before platelet-derived growth factor (PDGF) increased cytosolic Ca2+ concentration. This lag was not diminished at high concentrations of either porcine or human PDGF. Similar results were obtained in 3T3 cells loaded with quin-2 or fura-2. The differences in the effects of bombesin, vasopressin, and PDGF on Ca2+ movements were also substantiated by measurements of 45Ca2+ efflux and of cellular 45Ca2+ content. Activation of protein kinase C by phorbol esters inhibited Ca2+ mobilization induced by either bombesin or vasopressin. In contrast, phorbol esters had no effect on PDGF-induced cytosolic Ca2+ concentration increase or acceleration of 45Ca2+ efflux. Finally, bombesin and vasopressin caused a rapid increase in the production of inositol 1,4,5-trisphosphate and inositol 1,3,4-trisphosphate, whereas PDGF, even at a saturating concentration, exerted only a small effect. These results indicate that the signal transduction pathways activated by PDGF that lead to Ca2+ mobilization can be distinguished from those utilized by bombesin and vasopressin.
mesh_terms: D000818:Animals; D001839:Bombesin / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism*; D002460:Cell Line; D004261:DNA Replication / Q000187:drug effects; D005347:Fibroblasts / Q000187:drug effects* / Q000378:metabolism; D006801:Humans; D051379:Mice; D010703:Phorbol Esters / Q000494:pharmacology; D010716:Phosphatidylinositols / Q000378:metabolism; D010982:Platelet-Derived Growth Factor / Q000494:pharmacology*; D013552:Swine; D014667:Vasopressins / Q000494:pharmacology*
chemical_list: D010703:Phorbol Esters; D010716:Phosphatidylinositols; D010982:Platelet-Derived Growth Factor; D014667:Vasopressins; D001839:Bombesin; D002118:Calcium