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. 2024 Feb 27;15:1530. doi: 10.1038/s41467-024-45579-3

Fig. 1. Physiological concentration of bicarbonate ions activate GPR30 in vitro.

Fig. 1

a–f Calcium mobilisation assay in Fluo-8-loaded MCF-7 (MCF-GPR30, a–e) and HEK293 (HEK-GPR30, f) cells stably expressing human GPR30 (hGPR30). The increase in the intracellular calcium level was evaluated by maximum relative fluorescence units (RFU) minus minimum RFU (max − min). ATP activates endogenous purinergic receptors and serves as a positive control. a Cells treated with vehicle, oestradiol (E2, 10−11–10−7 M), aldosterone (10−11–10−7 M), and ATP (10−8–10−4 M). b Cells treated with vehicle, Dulbecco’s modified Eagle’s medium (DMEM), and ATP (25 µM). c MCF-GPR30 cells were treated with the mixed inorganic solution at various pH values, Minimum Essential Medium (MEM), and DMEM. d The depletion of sodium bicarbonate from the mixed inorganic solution abolished the increase in intracellular calcium levels in MCF-GPR30 cells. e, f Sodium bicarbonate and potassium bicarbonate, but not potassium chloride, increased intracellular calcium levels in MCF-GPR30 (e) and HEK-GPR30 (f) cells in a dose-dependent manner. Statistical analysis: two-tailed unpaired t-test with Dunnett’s correction (a) or Bonferroni’s correction (e and f) after two-way ANOVA. Two-tailed unpaired t-test with Holm-Šídák’s correction (b–d). Data are presented as mean values ± SEM. P values are shown if significant. ns indicates no significant difference. Source data are provided as a Source Data file.