Effects of platelet-derived growth factor on Ca2+ in 3T3 cells.
The effect of platelet-derived growth factor (PDGF) on cellular Ca2+ was examined in BALB/c-3T3 cells. PDGF induced: A decrease in cell 45Ca2+ content. An apparent increased rate of efflux of preloaded 45Ca2+. A decrease in residual intracellular 45Ca2+ remaining after rapid efflux. When added after the rapid phase of efflux of 45Ca2+ had occurred, an immediate decrease in post-efflux residual intracellular 45Ca2+. All of the observed changes in 45Ca2+ induced by PDGF are consistent with a rapid release of Ca2+ from an intracellular Ca2+ pool that has the slowest efflux and is relatively inaccessible to extracellular EDTA. When incubated with chlortetracycline (CTC), a fluorescent Ca2+ probe, 3T3 cell mitochondria became intensely fluorescent. Addition of PDGF resulted in a rapid decrease in CTC fluorescence intensity in both adherent and suspended 3T3 cells. The effects of PDGF on 3T3 cell Ca2+ stores and CTC fluorescence intensity were identical with the effects of the Ca2+ ionophore A23187 and of the proton ionophore carbonyl cyanide m-chlorophenyl hydrazone. Serum, which contains PDGF, also altered intracellular Ca2+ stores, but platelet-poor plasma, which does not contain PDGF, had no effect. EGF, insulin, and tetradecanoyl phorbol acetate (TPA), other factors which stimulate 3T3 cell growth, did not alter 3T3 cell Ca2+ stores. Release of Ca2+ from intracellular sequestration sites may be a mechanism by which PDGF stimulates cell growth.
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002460:Cell Line; D004815:Epidermal Growth Factor / Q000494:pharmacology; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism*; D007328:Insulin / Q000494:pharmacology; D051379:Mice; D008807:Mice, Inbred BALB C; D010982:Platelet-Derived Growth Factor / Q000494:pharmacology*; D013050:Spectrometry, Fluorescence; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
D007328:Insulin; D010982:Platelet-Derived Growth Factor; D004815:Epidermal Growth Factor; D013755:Tetradecanoylphorbol Acetate; D002118:Calcium