Glutathione Infusion Potentiates Glucose-Induced Insulin Secretion in Aged Patients With Impaired Glucose Tolerance

January 1992
Giuseppe Paolisso, MD; Dario Giugliano, MD; Gennaro Pizza, MD; Antonio Gambardella, MD; Paola Tesauro, MD; Michele Varricchio, MD; Felice D'Onofrio, MD
 

Objective

- To evaluate the effect of glutathione infusion on β-cell response to glucose in elderly people with impaired glucose tolerance (IGT).

Research Design and Methods

- Ten patients with normal glucose tol-erance 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 β-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 <15 mM. No effect of glutathione on insulin clearance and action was observed.

Conclusion

- Glutathione infusion enhances insulin secretion in elderly people with IGT.