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Calorie restriction reduces pinealectomy-induced insulin resistance by improving GLUT4 gene expression and its

Melissa M Zanquetta1, Patricia M Seraphim, Doris H Sumida

  • 1Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, Brazil.

Journal of Pineal Research
|August 23, 2003
PubMed

Insights

Pinealectomy reduces insulin sensitivity and glucose transporter type 4 (GLUT4) expression due to melatonin deficiency. Both melatonin replacement and calorie restriction in pinealectomized rats improve insulin sensitivity and GLUT4 regulation.

Area of Science:

  • Endocrinology
  • Metabolic Research
  • Chronobiology

Background:

  • Pinealectomy disrupts circadian rhythms and melatonin production.
  • Melatonin plays a role in metabolic regulation.
  • Insulin sensitivity is crucial for glucose homeostasis.

Purpose of the Study:

  • Investigate insulin sensitivity and GLUT4 expression in pinealectomized rats.
  • Determine the effects of melatonin and calorie restriction on these parameters.
  • Elucidate the role of melatonin in metabolic regulation.

Main Methods:

  • Pinealectomy and sham surgery in Wistar rats.
  • Melatonin replacement and calorie restriction interventions.
  • In vivo insulin tolerance tests (kITT).
  • Western blotting and Northern blotting for GLUT4 mRNA and protein analysis.

Main Results:

  • Pinealectomized rats exhibited reduced insulin sensitivity and GLUT4 expression in white adipose tissue.
  • Melatonin treatment restored insulin sensitivity and GLUT4 levels.
  • Calorie restriction significantly improved insulin sensitivity and GLUT4 expression/translocation in white adipose tissue.

Conclusions:

  • Melatonin deficiency following pinealectomy impairs insulin sensitivity and GLUT4 expression.
  • Melatonin replacement can reverse these metabolic deficits.
  • Calorie restriction offers a potential therapeutic strategy for improving metabolic health in conditions of melatonin deficiency.

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