Plasma GSH/GSSG affects glucose homeostasis in healthy subjects and non-insulin-dependent diabetics.
In healthy subjects (n = 10) and non-insulin-dependent (type II) diabetics (n = 10) matched for age [43.1 +/- 2.2 vs. 41 +/- 4.4 yr, P = not significant (NS)], body mass index (25.1 +/- 1.1 vs. 26 +/- 0.8 kg/m2, P = NS), gender ratio [5 males (M)/5 females (F) vs. 5M/5F], and mean arterial blood pressure (105 +/- 7 vs. 106 +/- 9 mmHg, P = NS), we determined the changes in insulin secretion and action after glutathione infusion (15 mg/min) and the relative increase in the plasma reduced (GSH)/oxidized (GSSG) glutathione ratio. The rise in the plasma GSH/GSSG ratio significantly improved total body glucose disposal in healthy subjects and in diabetic patients. In this latter group, GSH infusion potentiated the beta-cell response to glucose slightly. In controls and diabetics, insulin infusion with a simultaneous increase in the plasma GSH/GSSG ratio significantly enhanced nonoxidative glucose disposal without affecting oxidative glucose metabolism. After glutathione infusion, all metabolic and hormonal changes correlated with a significant decline in plasma membrane microviscosity. In conclusion, the plasma GSH/GSSG ratio seems to play a major role in the modulation of glucose homeostasis mainly in diabetics.
Paolisso
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G
Department of Geriatric Medicine and Metabolic Diseases, 1st Medical School, University of Naples, Italy.
Di Maro
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Pizza
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D'Amore
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Sgambato
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Tesauro
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Varricchio
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D'Onofrio
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D000328:Adult; D003924:Diabetes Mellitus, Type 2 / Q000378:metabolism*; D004910:Erythrocyte Membrane / Q000502:physiology; D005260:Female; D005947:Glucose / Q000378:metabolism*; D015309:Glucose Clamp Technique; D005951:Glucose Tolerance Test; D005978:Glutathione / Q000031:analogs & derivatives* / Q000097:blood*; D019803:Glutathione Disulfide; D006706:Homeostasis; D006801:Humans; D008297:Male; D012016:Reference Values; D014783:Viscosity
D005978:Glutathione; D005947:Glucose; D019803:Glutathione Disulfide