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Research Paper Volume 6, Issue 3 pp 207—214

Hexosamine pathway but not interstitial changes mediates glucotoxicity in pancreatic β-cells as assessed by cytosolic Ca2+ response to glucose

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Figure 3.

High (22.3 mM) glucose in culture impaired subsequent [Ca2+]i responses to physiologic glucose challenge in pancreatic β-cells, while L-glucose and increases in osmolarity, insulin and ATP had no or weaker effects. A, [Ca2+]i responses to 8.3 mM glucose (8.3G), 300 μM tolbutamide (Tolb), and 10 mM arginine (Arg) in single β-cells following control culture with 5.6 mM glucose. A representative of 41 cells (N=41). B, [Ca2+]i responses to 8.3G, Tolb and Arg in β-cells following culture with 22.3 mM glucose. N=17. C-F, [Ca2+]i responses to 8.3G, Tolb and Arg in β-cells following culture with 16.7 mM L-glucose (C; N=40), 16.7 mM mannitol (D; N=14), 10−5 M insulin (E; N=21), and 10−5 M ATP (F; N= 39) in the presence of 5.6 mM D-glucose.