Regulation of Insulin-Like Growth Factor 2 by Oocyte-Secreted Factors in Primary Human Granulosa Cells

J Clin Endocrinol Metab. 2020 Jan 1;105(1):327-335. doi: 10.1210/clinem/dgz057.


Context: Human granulosa cells (hGCs) produce and respond to insulin-like growth factor 2 (IGF2) but whether the oocyte participates in IGF2 regulation in humans is unknown.

Objective: To determine the role of oocyte-secreted factors (OSFs) such as growth differentiation factor 9 (GDF9) and bone morphogenetic protein 15 (BMP15) in IGF2 production by hGCs.

Design: Primary human cumulus GCs in culture.

Setting: University infertility center.

Patients or other participants: GCs of women undergoing in vitro fertilization.

Intervention(s): Cells treated with GDF9 and BMP15 in the presence of vehicle, follicle-stimulating hormone (FSH), dibutyryl cyclic-AMP (dbcAMP), or mothers against decapentaplegic homolog (SMAD) inhibitors.

Main outcome measure(s): Quantification of mRNA, protein, promoter activity, and DNA methylation.

Results: FSH stimulation of IGF2 (protein and mRNA) was significantly potentiated by the GDF9 and BMP15 (G+B) combination (P < 0.0001) in a concentration-dependent manner showing a maximal effect at 5 ng/mL each. However, GDF9 or BMP15 alone or in combination (G+B) have no effect on IGF2 in the absence of FSH. FSH stimulated IGF2 promoter 3 activity, but G+B had no effect on promoter activity. G+B potentiated IGF2 stimulation by cAMP. SMAD3 inhibitors inhibited G+B enhancement of IGF2 stimulation by FSH (P < 0.05) but had no effect on FSH induction. Moreover, inhibition of insulin-like growth factor receptor partially blocked G+B potentiation of FSH actions (P < 0.009).

Conclusions: For the first time, we show that the oocyte actively participates in the regulation of IGF2 expression in hGCs, an effect that is mediated by the specific combination of G+B via SMAD2/3, which in turn target mechanisms downstream of the FSH receptor.

Publication types

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

MeSH terms

  • Bone Morphogenetic Protein 15 / pharmacology
  • Cells, Cultured
  • Culture Media, Conditioned / chemistry
  • Culture Media, Conditioned / pharmacology*
  • Cyclic AMP / metabolism
  • Drug Combinations
  • Female
  • Follicle Stimulating Hormone / genetics
  • Follicle Stimulating Hormone / metabolism
  • Gene Expression Regulation / drug effects
  • Granulosa Cells / cytology*
  • Granulosa Cells / metabolism
  • Growth Differentiation Factor 9 / pharmacology
  • Humans
  • Insulin-Like Growth Factor II / genetics*
  • Insulin-Like Growth Factor II / metabolism
  • Oocytes / cytology
  • Oocytes / metabolism*
  • Primary Cell Culture / methods


  • Bone Morphogenetic Protein 15
  • Culture Media, Conditioned
  • Drug Combinations
  • GDF9 protein, human
  • Growth Differentiation Factor 9
  • IGF2 protein, human
  • Insulin-Like Growth Factor II
  • Follicle Stimulating Hormone
  • Cyclic AMP