Glucose reduces subplasmalemmal STIM1-YFP fluorescence in islet β-cells.
A–C, TIRF intensity recordings on epinephrine-identified β-cells (Epi, 5 μm) showing that increase of the glucose concentration from 3 to 20 mm reduces subplasmalemmal STIM1-YFP fluorescence. The glucose effect was partially reversed after reintroduction of 3 mm glucose (A) and complete reversal required glucose omission in islet β-cells (B and C). D, TIRF intensity recording of a β-cell with STIM1-YFP oscillations in 3 mm glucose (Gluc) that are reversibly inhibited by 20 mm glucose. E, TIRF intensity recording of the effect of increasing glucose concentrations within the 0–20 mm range on reduction of subplasmalemmal STIM1-YFP in a single β-cell. F, dose-response relationships for glucose-induced reduction of subplasmalemmal STIM1-YFP in β-cells. Mean values ± S.E., n = 9.