Fig. 4.

Diabetes alters islet NAD(P)H generation. a Relative change in NAD(P)H fluorescence (F/F₀) recorded simultaneously in groups of control (above, n = 58) or 2-week diabetic βV59M (below, n = 54) islets. Each trace represents an individual islet. Data are colour coded according to a ‘rainbow’ LUT, i.e. from violet (low value) to red (high value). b Basal NAD(P)H autofluoresence at 2 mM glucose in control (white, n = 396 islets) and 2-week diabetic islets (black, n = 200 islets). Mean ± s.e.m., t test ***p < 0.001. c Change in NAD(P)H autofluoresence in response to glucose (6 or 20 mM), to 20 mM glucose + 10 µM oligomycin and to 20 mM glucose + 4 µM FCCP in control (white, n = 60–257 islets) and 2-week diabetic βV59M islets (black, n = 152–194 islets). d Change in mitochondrial membrane potential, as assessed by TMRE (tetramethylrhodamine ethyl ester) fluorescence, in response to glucose (6 or 20 mM), to 20 mM glucose + 10 µM oligomycin and to 20 mM glucose + 4 µM FCCP in control (black, n = 83–199 islets) and 2-week diabetic islets (red, n = 111–248 islets). c, d Data are normalised to the level in 2 mM glucose. Mean ± s.e.m. Kruskal–Wallis analysis of variance with Dunn post hoc test. *p < 0.05. e–g NADH and NADPH autofluorescence measured with fluorescence lifetime imaging microscopy in control (n = 21) and 2-week diabetic islets (n = 30) exposed to 2 (white bars) or 20 mM (black bars) glucose. Mean ± s.e.m. t test *p < 0.05, **p < 0.01, ***p < 0.001. e NAD(P)H autofluorescence. f Fluorescence lifetime of enzyme-bound NADH + NADPH autofluorescence signal. g Relative NADH and NADPH concentrations