Metformin: direct inhibition of rat ovarian theca-interstitial cell proliferation

Fertil Steril. 2012 Jul;98(1):207-14. doi: 10.1016/j.fertnstert.2012.04.010. Epub 2012 May 17.


Objective: To determine whether metformin has direct effects on ovarian theca-interstitial (T-I) cell proliferation through activation of adenosine monophosphate-activated protein kinase (AMPK).

Design: In vitro experimental study.

Setting: Academic medical center laboratory.

Animal(s): Immature Sprague-Dawley female rats.

Intervention(s): Ovarian T-I cells were isolated, purified, and cultured in the absence (control) or presence of insulin (1 μg/mL) with or without metformin or other activators/inhibitors of AMPK (AICAR, compound C).

Main outcome measure(s): Proliferation assessed by determination of expression levels of proteins involved in cell cycle progression, cyclin D3, and cyclin-dependent kinase 4 (CDK4) with Western blot analysis, and determination of DNA synthesis with bromodeoxyuridine (BrdU) incorporation assay; activation of AMPK, Erk1/2, and S6K1 determined by Western blot analysis with the use of antibodies specific for the phosphorylated (activated) forms.

Result(s): Metformin inhibited insulin-induced ovarian T-I cell proliferation and the up-regulation of the cell cycle regulatory proteins, cyclin D3 and CDK4. Metformin independently activated AMPK in a dose-dependent manner. Treatment with metformin inhibited insulin-induced activation of Erk1/2 and S6K1. This effect was reversed with the addition of compound C, a known AMPK inhibitor.

Conclusion(s): Metformin directly inhibits proliferation of ovarian T-I cells via an AMPK-dependent mechanism. These findings further validate the potential benefits of metformin in the treatment of conditions associated with hyperinsulinemia and excessive growth of ovarian T-I cells (such as polycystic ovary syndrome).

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • AMP-Activated Protein Kinases / metabolism
  • Animals
  • Cell Cycle Checkpoints / drug effects
  • Cell Cycle Checkpoints / physiology
  • Cell Proliferation / drug effects*
  • Cells, Cultured
  • Drug Evaluation, Preclinical
  • Enzyme Activation / drug effects
  • Female
  • Hypoglycemic Agents / pharmacology
  • MAP Kinase Signaling System / drug effects
  • Metformin / pharmacology*
  • Ovary / cytology
  • Ovary / drug effects*
  • Rats
  • Rats, Sprague-Dawley
  • Ribosomal Protein S6 Kinases / metabolism
  • Theca Cells / cytology
  • Theca Cells / drug effects*
  • Theca Cells / physiology


  • Hypoglycemic Agents
  • Metformin
  • Ribosomal Protein S6 Kinases
  • Rps6kb1 protein, rat
  • AMP-Activated Protein Kinases