Resveratrol enhances insulin secretion by blocking K(ATP) and K(V) channels of beta cells.
The present study investigated the effect of resveratrol on the electrophysiology and insulin secretion of pancreatic beta cells, and examined resveratrol-induced alterations in insulin levels and plasma glucose of normal and streptozotocin-induced diabetic rats. Whole-cell voltage clamp study in the MIN6 cell, a mouse beta cell line, revealed that resveratrol significantly inhibited ATP-sensitive K(+) current at 3 micromol/l, and voltage-gated K(+) currents at 30 micromol/l. Ca(2+)-activated K(+) current was activated by resveratrol at 100 micromol/l. In MIN6 cells stained with membrane potential dye DiBAC(4)(5), resveratrol markedly depolarized membrane potential at the concentrations of 3-100 micromol/l. Insulin secretion was increased in the presence of resveratrol in MIN6, Hit-T15, and RIN-m5F cells. Resveratrol (3 mg/kg, i.p.) increased insulin secretion associated with a lowering in plasma glucose in normal rats, but not in streptozotocin-diabetic rats within the initial 60 min. In conclusion, resveratrol can act as an insulin-secretagogue through I(KATP) and I(KV) inhibition which can contribute to plasma glucose lowering effect in normal rats.
Chen
Wen-Pin
WP
Institute of Pharmacology, National Taiwan University Medical College, Taipei, Taiwan.
Chi
Tzong-Cherng
TC
Chuang
Lee-Ming
LM
Su
Ming-Jai
MJ
D000818:Animals; D001786:Blood Glucose / Q000032:analysis; D045744:Cell Line, Tumor; D006224:Cricetinae; D003921:Diabetes Mellitus, Experimental / Q000097:blood; D007328:Insulin / Q000097:blood / Q000378:metabolism*; D000078790:Insulin Secretion; D050417:Insulin-Secreting Cells / Q000187:drug effects* / Q000502:physiology; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects; D051379:Mice; D026902:Potassium Channel Blockers / Q000494:pharmacology*; D015221:Potassium Channels / Q000187:drug effects* / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar; D000077185:Resveratrol; D013267:Stilbenes / Q000494:pharmacology*
D001786:Blood Glucose; D007328:Insulin; D026902:Potassium Channel Blockers; D015221:Potassium Channels; D013267:Stilbenes; D000077185:Resveratrol