Nuclear Ca2+ Transients are Altered by High Glucose. A) Nuclear Ca2+ responses to vasopressin and thapsigargin (TSG) in A7r5 cells grown in medium glucose or high glucose conditions are shown. Both the vasopressin (added at time 0) and the TSG (added at the arrow) responses were blunted in the nuclei of cells grown in high glucose. (n = 15 cells/group, p < 0.0001) B) The mean peak amplitude of the Ca2+ response to vasopressin did not change significantly in the cytoplasm when cells were grown in high glucose. However, the nuclear compartment showed significant reduction of the vasopressin response in high glucose (n = 94 cells) versus medium glucose (n = 37). (p < 0.001; indicated by *) C) The mean peak amplitude of the thapsigargin (TSG) response did not change significantly in the cytoplasmic compartment with high glucose exposure, but was significantly blunted in the nuclear compartment (n = 37). (p < 0.001; indicated by *).