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Glucose-induced insulin mRNA accumulation is impaired in islets from neonatal streptozotocin-treated rats

I Briaud1, C Rouault, D Bailbé

  • 1Pacific Northwest Research Institute, Seattle, WA 98122, USA.

Hormone and Metabolic Research = Hormon- Und Stoffwechselforschung = Hormones Et Metabolisme
|April 29, 2000
PubMed

Insights

High blood sugar impairs insulin gene regulation in a rat model of type 2 diabetes. Glucose fails to boost insulin mRNA in affected islets, indicating defective beta-cell function.

Area of Science:

  • Endocrinology
  • Molecular Biology
  • Diabetes Research

Background:

  • The glucose toxicity hypothesis suggests hyperglycemia impairs beta-cell function in type 2 diabetes.
  • Rodent models support this, but glucose's effect on insulin mRNA accumulation in chronic hyperglycemia is understudied.
  • Insulin mRNA accumulation is vital for normal beta-cell physiology.

Purpose of the Study:

  • To investigate if glucose-induced insulin mRNA accumulation is impaired in neonatal streptozotocin-treated (n0-STZ) rats.
  • To assess beta-cell response to hyperglycemia in a non-obese model of non-insulin-dependent diabetes mellitus.

Main Methods:

  • Islets of Langerhans were isolated from n0-STZ and control rats.
  • Islets were cultured for 24 hours with low (2.8 mmol/L) or high (16.7 mmol/L) glucose concentrations.
  • Insulin mRNA levels were quantified using Northern analysis.

Main Results:

  • In control islets, high glucose significantly increased insulin mRNA levels (over twofold).
  • In n0-STZ rat islets, glucose exposure did not significantly alter insulin mRNA levels.
  • This indicates impaired glucose regulation of insulin gene expression in this model.

Conclusions:

  • Glucose-induced insulin mRNA accumulation is impaired in the n0-STZ rat model.
  • This finding suggests a defect in insulin gene regulation by glucose in beta-cells of this diabetes model.
  • The study highlights impaired beta-cell response to hyperglycemia in type 2 diabetes.

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