Fig. 4.

Effect of insulin on cytosolic Ca²⁺. a Effects of insulin on [Ca²⁺]_i in δ cells in intact islets exposed to 4 mM glucose. Two representative traces are shown. b, c Frequency (b) and amplitude (c) of [Ca²⁺]_i oscillations at 4 mM glucose in the absence and presence of insulin. *p < 0.05 vs 4 mM glucose (n = 54 δ cells in 11 islets from 8 mice of both sexes), Student’s t-test. d Effects of insulin (100 nM) on somatostatin secretion at 4 mM glucose in the absence and presence of the SERCA inhibitor thapsigargin (25 μM). ***p < 0.001 vs 4 mM glucose; ^††p < 0.01 vs 4 mM glucose and insulin in the absence of thapsigargin (n = 10 experiments/4 male mice), one-way ANOVA followed by Sidak’s post hoc test. Data in b–d are presented as dot plots of individual experiments and/or mean values ± S.E.M. of all experiments with the experimental series