Species-Related Differences in the Proteome of Rat and Human Pancreatic Beta Cells

Figure 3

Beta cell-selective MDH1 expression in rat but not human pancreas. (a) A monoclonal antibody raised against recombinant human MDH1 fragment results in islet-restricted staining pattern in rat pancreas. In human pancreas, MDH1 fluorescence in islets does not exceed background level of surrounding exocrine tissue, as evidenced by intensity plotted along the dotted blue line, while in rat it shows a strong islet-restricted level. Representative of 3 organs analyzed for each species. (b–d) In rat, cellular MH1/MDH2 level increases during postnatal beta cell maturation from neonatal period to 10 weeks (c). In 10-week-old cells, beta cells FACS-sorted (b) for higher 7.5 mM glucose-induced NADH have higher MDH1/MDH2, and overall (d), the increment of cellular NADH acutely after 10 versus 0 mM glucose-stimulation is linearly correlated to cellular MDH1/MDH2 in the indicated rat beta cell phenotypes.

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