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The thyroid hormone receptor-beta agonist GC-1 induces cell proliferation in rat liver and pancreas

Amedeo Columbano1, Monica Pibiri, Manuela Deidda

  • 1Department of Toxicology, Oncology, and Molecular Pathology Unit, University of Cagliari, Via Porcell 4, 09124 Cagliari, Italy. columbano@unica.it

Endocrinology
|April 1, 2006
PubMed

Insights

The thyroid hormone receptor beta (TRbeta)-selective agonist GC-1 strongly stimulates cell proliferation in rat liver and pancreas. This suggests TRbeta mediates the mitogenic effects of thyroid hormone and related compounds.

Area of Science:

  • Endocrinology
  • Molecular Biology
  • Cell Biology

Background:

  • Thyroid hormones regulate crucial cellular functions through thyroid hormone nuclear receptors (TRs).
  • Novel TRbeta-selective agonists, like GC-1, show therapeutic potential for metabolic disorders.
  • Investigating GC-1's effects on non-traditional target organs is essential.

Purpose of the Study:

  • To determine the impact of GC-1 on cell proliferation in rat liver and pancreas.
  • To elucidate the role of TRbeta in mediating mitogenic activities.

Main Methods:

  • Rats were administered GC-1 at varying doses and time points.
  • Hepatic and pancreatic cell proliferation assessed via bromodeoxyuridine incorporation.
  • Cell cycle-related gene expression analyzed using Northern and Western blotting.

Main Results:

  • GC-1 significantly stimulated hepatocyte proliferation without inducing tissue injury.
  • GC-1 increased cyclin D1 mRNA levels but not c-jun or c-fos expression.
  • Massive pancreatic cell proliferation was observed following GC-1 treatment.

Conclusions:

  • The TRbeta-selective agonist GC-1 acts as a potent mitogen for hepatocytes and pancreatic acinar cells.
  • TRbeta receptor is implicated as the mediator of mitogenic activity for thyroid hormone and thyromimetics.

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