The effect of garlic oil on insulin secretion in HIT-T15 cells
Journal
Nutritional Sciences Journal
Journal Volume
36
Journal Issue
4
Pages
125-135
Date Issued
2011
Author(s)
Abstract
It is known that glucose toxicity suppresses insulin secretion. Using an islet £] cell line (HIT-T15), the present study investigated the effect of garlic oil (GO) on insulin secretion. Cells were pre-cultured in various concentrations of glucose (5.5, 11.1, and 33.3 mM) with or without GO (1?100 £gg/ml) for 24 h followed by the determination of cell validity and insulin secretion in the pre-culture. After washing cells after the pre-culture, glucose-stimulated insulin secretion (GSIS), the cellular ATP content, and glucose transport kinetics were determined, The effect of GO on the oxidative condition of cells cultured under a hyperglycemic condition was also investigated. It was found that GO (1?10 £gg/ml) improved insulin secretion of cells in the pre-culture medium to a level similar to that of glibenclimide; it also improved the GSIS in association with elevated cellular ATP, decreased Km, and increased Vmax of the glucose transport system. Hyperglycemia increased thiobarbituric acid reactive substances (TBARS) level and decreased superoxide dismutase (SOD) activity in cells, although the total glutathione (GSH) content, the activities of glutathione peroxidase (GPx) and glutathione reductase (GR) remained unaffected. GO improved SOD activity of cells cultured under a hyperglycemic condition; however, it did not ameliorate the increase in TBARS in these cells. In conclusion, GO acutely improved GSIS in the HIT-T15 £] cell line cultured under normal and hyperglycemic conditions which was associated with increased glucose utilization by these cells but not through an antioxidant effect.
Subjects
ATP
Garlic oil
Glucose transporter
Glucose-stimulated insulin secretion (GSIS)
HIT-T15 cell line
Insulin
Type
journal article