Objective To explore the calcium homeostasis interrupted by fenvalerate and the effect of fenvalerate on cell proliferation.Methods RT-PCR was used to detect the expression of IP3Rs and RyRs in GC-2spd (ts) cells and Immunofluorescence assay was used to localize RyRs and IP3Rs within the cells.Realtime-PCR was carried out to investigate the roles of fenvalerate on the two receptors and the measurement of calcium homeostasis mediated by fenvalerate was evaluated by confocal laser scanning microscope.Moreover,the effect of fenvalerate on cell proliferation was detected by cell proliferation assays.Finally,we tested the cell phase which was affected by fenvalerate.Statistically significant differences between the treatments and the control were determined by one-way ANOVA and LSD multiple comparison procedure.Results All IP3R isoforms and RyR1 was detected in GC-2 cells and Iumunofluorescence assay showed that fluorescent signals for the IP3Rs were visualized through out the cell while labeling of RyRs was most intense in the region of cytoplasm.Data of Realtime-PCR showed that mRNA expression of RyR1,IP3R1,IP3R3 were affected by fenvalerate while IP3R2 was not significantly altered.Furthermore,we discovered that fenvalemte affected the Ca2 + homeostasis,inducing Ca2 + transients via both intracell~ar Ca2 + release and extracellular Ca2+ influx.Ca2+ influx was via store-operated channel (SOC).Therefore,the role of calcium on cell proliferation was assessed and we found that fenvalerate inhibited cell outgrowth.Moreover,2-APB,known as IP3Rs antagonist,inhibited cell proliferation in a dose-dependent way.Finally,analysis of cell cycle progression of GC-2 cells cultured with fenvalerate and 2-APB demonstrated S-phase accumulation.Conclusions Our results demonstrate that fenvalerate-induced Ca2 + transients from both calcium release through RyRs or IP3Rs and calcium influx via SOC.IP3Rs seem to serve a predominant role in triggering Ca2+ transients which could participated to the regulation of GC-2 cell proliferation.