Fig. 5

Delta cell activity is impaired in prediabetes. a Representative normalized traces of GCaMP3 signals measured in vivo in delta cells from animals fed with control (CD, black lines) or HFD (orange lines). As in Fig. 1, the yellow-shaded area marks the time period used for measurements of glucose responses. b Spiking delta cell Ca²⁺ peak amplitude signal during basal, glucose, or recovery time periods normalized to basal conditions in CD (basal: n = 358; glucose: n = 588; recovery: n = 1060 peaks from n = 23 cells in four islets total and one islet per animal) or HFD (basal: n = 127; glucose: n = 224; recovery: n = 353 peaks from n = 14 cells in four islets total and one islet per animal for a total of four animals) animals. Data shown as fold change from the basal state. c Physical length of the delta cell filopodia in its longest axis (tip to cell body) from islets in situ from CD (n = 4 mice, 33 islets total, n = 33 delta cells) or HFD (n = 4 mice, 42 islets total, n = 42 delta cells) animals. Right, maximum projection images of delta cells acquired with confocal microscopy in CD or HFD animals. Scale bars, a 50  μm and (H), 10  μm. Statistics: b data shown for false discovery rate (FDR, q < 0.005 for discovery): **q < 0.002, p < 0.001 by OneWay Anova with a multi-comparison test using a two-stage linear step-up procedure of Benjamini, Krieger, and Yakutieli. In c, **p = 0.0038 by unpaired, two-tailed Student’s t-test. Error bars represent the 95% confidence interval (C.I.) of the mean. For b, c source data are provided as a Source Data file