Islets from diabetic mice show abnormalities in pH
regulation: Cultured islets loaded with SNARF5-AM were excited at 514 nm, and emission fluorescence was collected at 580 and 630 nm. Islet pHi was calculated from the ratio of emission fluorescence. Acetate (40 mM) or NH4Cl (5 mM) was added where indicated. One representative recording for each condition is shown. 10–20 islets were imaged for each condition. A. Wild type islets: Basal pHi range 6.9–7.1. Fast recovery from drastic pHi-change produced by acid or base load. B. Islets from diabetic KK mice: Basal pHi range 7.3–7.5. Recovery from acid load is slower. Recovery from base load is followed by overcompensation. C. Islets from diabetic NON mice: Basal pHi similar to wild type controls. Response to base load is slower. Recovery is from acid/base load is followed by overcompensation.