Impaired glucose tolerance and mild hyperglycemia in sucrose-fed rats does not impair insulin secretion.
We fed normal rats a high sucrose diet in order to test the hypothesis that mild hyperglycemia can induce defects in pancreatic beta-cell function and impair glucose-stimulated insulin release. Rats provided with free access to a sucrose solution (35%) voluntarily consumed 50% more carbohydrate than control per day. After 7 days of sucrose feeding, glucose tolerance was significantly impaired; the area under the glucose tolerance test curve (GTT) was 683 +/- 61 mmol/120 min compared with 472 +/- 56 mmol/120 min in controls (P < 0.05). Impaired glucose tolerance was still present after a further 12 days (area under the GTT: 749 +/- 99 mmol/120 min). Sucrose-fed rats were significantly (P < 0.05) hyperglycemic by 1.5 mmol/l over controls. When insulin secretion was assessed in vivo and in vitro in control and sucrose-fed rats, no significant differences were apparent in plasma samples collected over a 1-h period or in statically incubated or perifused isolated pancreatic islets. In addition, the rates of glucose utilisation and oxidation were normal in islets from sucrose-fed rats. These data do not support the hypothesis that minimal hyperglycemia is sufficient to impair glucose-stimulated insulin release.
Department of Physiology, St. Mary's Hospital Medical School, Imperial College, London, UK.
M
M
Wilson
S J
SJ
Hughes
D000818:Animals; D001120:Arginine / Q000494:pharmacology; D001786:Blood Glucose / Q000378:metabolism; D002478:Cells, Cultured; D004040:Dietary Carbohydrates; D019422:Dietary Sucrose; D002149:Energy Intake; D005947:Glucose / Q000378:metabolism / Q000494:pharmacology*; D018149:Glucose Intolerance / Q000097:blood / Q000503:physiopathology*; D005951:Glucose Tolerance Test; D006943:Hyperglycemia / Q000097:blood / Q000503:physiopathology*; D007328:Insulin / Q000097:blood / Q000378:metabolism*; D000078790:Insulin Secretion; D007515:Islets of Langerhans / Q000187:drug effects / Q000378:metabolism*; D007700:Kinetics; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D012016:Reference Values
D001786:Blood Glucose; D004040:Dietary Carbohydrates; D019422:Dietary Sucrose; D007328:Insulin; D001120:Arginine; D005947:Glucose