Abstract
Human insulin was glycated under hyperglycemic reducing conditions and a novel diglycated form (M(r) 6135.1 Da) was purified by RP-HPLC. Endoproteinase Glu-C digestion combined with mass spectrometry and automated Edman degradation localized glycation to Gly(1) and Phe(1) of the insulin A- and B-chains, respectively. Intraperitoneal (i.p.) administration of diglycated insulin to mice alone or in combination with glucose (7 nmol/kg) resulted in a 43-61% and 11-34% reduction in glucose lowering activity, respectively, compared with native insulin. Consistent with these findings, diglycated insulin (10(-9) to 10(-7) mol/liter) was 22-38% less effective (P < 0.001) than native insulin in stimulating glucose uptake, glucose oxidation and glycogen production in isolated mouse abdominal muscle.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Amino Acids / analysis
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Animals
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Biological Transport / drug effects
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Blood Glucose / drug effects
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Blood Glucose / metabolism
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Chromatography, High Pressure Liquid
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Deoxyglucose / metabolism
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Glucose / metabolism
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Glucose / pharmacology
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Glycogen / biosynthesis
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Glycoproteins / chemistry
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Glycoproteins / isolation & purification
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Glycoproteins / pharmacology
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Glycoproteins / therapeutic use
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Glycosylation
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Humans
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Hyperglycemia / blood
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Hyperglycemia / drug therapy*
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Hyperglycemia / metabolism
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Injections, Intraperitoneal
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Insulin / analogs & derivatives*
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Insulin / chemistry
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Insulin / pharmacology*
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Insulin / therapeutic use
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Male
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Mass Spectrometry
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Mice
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Mice, Inbred Strains
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Muscle, Smooth / drug effects
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Muscle, Smooth / metabolism
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Serine Endopeptidases / metabolism
Substances
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Amino Acids
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Blood Glucose
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Glycoproteins
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Insulin
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Glycogen
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Deoxyglucose
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Serine Endopeptidases
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glutamyl endopeptidase
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Glucose