Pharmacological doses of vitamin E and insulin action in elderly subjects.
Twenty elderly (77 +/- 0.4 y), nonobese [body mass index (in kg/m2) 26.4 +/- 0.5] subjects with normal glucose tolerance were submitted to a euglycemic hyperinsulinemic (3.5 pmol.min/kg) glucose clamp in a double-blind, crossover, randomized procedure after 4 mo treatment with either vitamin E (900 mg d-alpha-tocopherol/d, Ephynal; Roche, Milan, Italy) or placebo. Body mass index was practically unchanged throughout the study. After the glucose clamp, insulin-mediated stimulation 2 of whole-body glucose disposal (18.4 +/- 0.5 vs 26.1 +/- 0.6 mumol.min/kg lean body mass P < 0.02) was significantly potentiated by vitamin E rather than placebo administration. Furthermore, net changes in plasma vitamin E concentrations correlated with net changes in insulin-stimulated whole-body glucose disposal (r = 0.60 P < 0.003). Plasma vitamin E concentrations seem to play an important role in the modulation of insulin action in elderly people.
Paolisso
G
G
Department of Geriatric Medicine and Metabolic Diseases, II University of Naples, Italy.
Di Maro
G
G
Galzerano
D
D
Cacciapuoti
F
F
Varricchio
G
G
Varricchio
M
M
D'Onofrio
F
F
D000368:Aged; D001786:Blood Glucose / Q000032:analysis; D015992:Body Mass Index; D004311:Double-Blind Method; D005215:Fasting / Q000378:metabolism; D005260:Female; D005978:Glutathione / Q000097:blood; D006801:Humans; D007328:Insulin / Q000097:blood / Q000502:physiology*; D008055:Lipids / Q000097:blood; D008297:Male; D010084:Oxidation-Reduction; D010100:Oxygen / Q000097:blood; D014810:Vitamin E / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology*
D001786:Blood Glucose; D007328:Insulin; D008055:Lipids; D014810:Vitamin E; D005978:Glutathione; D010100:Oxygen