Glutathione infusion potentiates glucose-induced insulin secretion in aged patients with impaired glucose tolerance.
OBJECTIVE
To evaluate the effect of glutathione infusion on beta-cell response to glucose in elderly people with impaired glucose tolerance (IGT).


METHODS
Ten patients with normal glucose tolerance and 10 patients with IGT were matched for age (mean +/- SE, 72.1 +/- 2.8 vs. 71.0 +/- 3.4 yr), body mass index (23.1 +/- 1.1 vs. 22 +/- 2.1 kg/m2), and sex (6/4 vs. 5/5, men/women) underwent glutathione infusion (10 mg/min) under basal conditions and during 75-g oral glucose tolerance tests and intravenous glucose tolerance tests (0.33 g.kg body wt-1.3 min-1). Patients with IGT were also submitted to euglycemic-hyperinsulemic and hyperglycemic glucose clamps.


RESULTS
In subjects with normal glucose tolerance, glutathione infusion failed to affect beta-cell response to glucose. In contrast, glutathione significantly potentiated glucose-induced insulin secretion in patients with IGT. Furthermore, in the latter group studied by hyperglycemic clamps, glutathione infusion significantly potentiated the beta-cell response to glucose when plasma glucose levels varied between 10 and 15 mM. This effect disappeared at plasma glucose levels greater than 15 mM. No effect of glutathione on insulin clearance and action was observed.


CONCLUSIONS
Glutathione infusion enhances insulin secretion in elderly people with IGT.
Paolisso
G
G
Institute of Geriatric Medicine, First Medical School; University of Naples, Italy.
Giugliano
D
D
Pizza
G
G
Gambardella
A
A
Tesauro
P
P
Varricchio
M
M
D'Onofrio
F
F
D000368:Aged; D001786:Blood Glucose / Q000378:metabolism*; D005934:Glucagon / Q000097:blood / Q000378:metabolism; D015309:Glucose Clamp Technique; D005951:Glucose Tolerance Test; D005978:Glutathione / Q000627:therapeutic use*; D006801:Humans; D006943:Hyperglycemia / Q000097:blood; D007328:Insulin / Q000097:blood / Q000378:metabolism*; D000078790:Insulin Secretion; D013997:Time Factors
D001786:Blood Glucose; D007328:Insulin; D005934:Glucagon; D005978:Glutathione