Abstract
Dimethyl amiloride (DMA) enhances insulin secretion in the pancreatic beta-cell. DMA also enhances time-dependent potentiation (TDP) and enables TDP to occur in situations where it is normally absent. As we have demonstrated before, these effects are mediated in part through inhibition of neuronal nitric oxide synthase (nNOS), resulting in increased availability of arginine. Thus both DMA and arginine have the potential to correct the secretory defect in diabetes by enabling or enhancing TDP. In the current study we have demonstrated the ability of these agents to improve blood glucose homeostasis in three mouse models of type 2 diabetes. The pattern of TDP under different conditions indicates that inhibition of NOS is not the only mechanism through which DMA exerts its positive effects. Thus we also have explored another possible mechanism through which DMA enables/enhances TDP, via the activation of mitochondrial alpha-ketoglutarate dehydrogenase.
Publication types
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Research Support, N.I.H., Extramural
MeSH terms
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Amiloride / analogs & derivatives*
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Amiloride / pharmacology
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Amino Acids, Cyclic / pharmacology
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Animals
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Arginine / pharmacology*
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Blood Glucose / drug effects
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Blood Glucose / metabolism*
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Diabetes Mellitus, Type 2 / blood
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Diabetes Mellitus, Type 2 / drug therapy*
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Diabetes Mellitus, Type 2 / metabolism
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Disease Models, Animal
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Drug Synergism
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Homeostasis / drug effects
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Hydrogen-Ion Concentration / drug effects
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Insulin / blood
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Insulin / metabolism
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Insulin Secretion
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Insulin-Secreting Cells / drug effects*
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Insulin-Secreting Cells / metabolism
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Keto Acids / pharmacology
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Ketoglutarate Dehydrogenase Complex / antagonists & inhibitors
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Ketoglutarate Dehydrogenase Complex / metabolism
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Male
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Mice
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Mice, Inbred C57BL
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Mice, Knockout
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Mitochondria / drug effects
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Mitochondria / enzymology
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Mitochondria / metabolism
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NG-Nitroarginine Methyl Ester / pharmacology
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Nitric Oxide Synthase Type I / deficiency
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Nitric Oxide Synthase Type I / genetics
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Sodium-Calcium Exchanger / antagonists & inhibitors
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Sodium-Calcium Exchanger / pharmacology
Substances
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Amino Acids, Cyclic
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Blood Glucose
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Insulin
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Keto Acids
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Sodium-Calcium Exchanger
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2-aminobicyclo(2,2,1)heptane-2-carboxylic acid
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5-dimethylamiloride
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Amiloride
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alpha-ketoisocaproic acid
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Arginine
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Nitric Oxide Synthase Type I
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Ketoglutarate Dehydrogenase Complex
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NG-Nitroarginine Methyl Ester