Correlation between pancreatic islet uncoupling protein-2 (UCP2) mRNA concentration and insulin status in rats

Int J Exp Diabetes Res. 2000;1(3):185-93. doi: 10.1155/edr.2000.185.


Hypothesizing that UCP2 may influence insulin secretion by modifying the ATP/ADP ratio within pancreatic islets, we have investigated the expression of intraislet UCP2 gene in rats showing insulin oversecretion (non-diabetic Zucker fa/fa obese rats, glucose-infused Wistar rats) or insulin undersecretion (fasting and mildly diabetic rats). We found that in Zucker fa/fa obese rats, hyperinsulinemia (1222+/-98 pmol/l vs. 128+/-22 pmol/l in lean Zucker rats) was accompanied by a significant increase in UCP2 mRNA levels. In rat submitted to a 5 day infusion with glucose, hyperinsulinemia (1126+/-101 pmol/l vs. 215+/-25 pmol/l in Wistar control rats), coincided with an enhanced intraislet UCP2 gene expression, whereas a 8h or a 2 day-infusion did not induce significant changes in UCP2 mRNA expression. In rats made hypoinsulinemic and mildly diabetic by the injection of a low dose of streptozotocin, and in 4-day-fasting rats (plasma insulin 28+/-5 pmol/l) UCP2 gene expression was sharply decreased. A 3-day-fast was ineffective. The data show the existence of a time-dependent correlation between islet mRNA UCP2 and insulin that may be interpreted as an adaptative response to prolonged insulin excess.

MeSH terms

  • Analysis of Variance
  • Animals
  • Blood Glucose / metabolism
  • Fasting
  • Gene Expression Regulation / drug effects
  • Gene Expression Regulation / physiology*
  • Glucose / pharmacology
  • Glucose Clamp Technique
  • Hyperinsulinism / physiopathology
  • Infusions, Intravenous
  • Insulin / blood
  • Insulin / metabolism*
  • Insulin / pharmacology
  • Insulin Secretion
  • Ion Channels
  • Islets of Langerhans / metabolism
  • Islets of Langerhans / physiology*
  • Islets of Langerhans / physiopathology
  • Kinetics
  • Male
  • Membrane Transport Proteins*
  • Mitochondrial Proteins*
  • Obesity / genetics
  • Obesity / physiopathology*
  • Proteins / genetics*
  • RNA, Messenger / genetics*
  • RNA, Messenger / metabolism
  • Rats
  • Rats, Wistar
  • Rats, Zucker
  • Species Specificity
  • Transcription, Genetic / drug effects
  • Transcription, Genetic / physiology
  • Uncoupling Agents
  • Uncoupling Protein 2


  • Blood Glucose
  • Insulin
  • Ion Channels
  • Membrane Transport Proteins
  • Mitochondrial Proteins
  • Proteins
  • RNA, Messenger
  • Ucp2 protein, rat
  • Uncoupling Agents
  • Uncoupling Protein 2
  • Glucose