BACKGROUND: This study seeks to clarify cell cycle dynamics of granulosa cells following hCG and elucidate the expression of epidermal growth factor (EGF)-like ligands during luteinization. METHODS: Granulosa cells were obtained from rhesus macaques undergoing controlled ovarian stimulation protocols before or after an ovulatory hCG bolus. Cell cycle characteristics were determined by flow cytometry and levels of EGF receptor (EGFR), amphiregulin (AREG), epiregulin (EREG) and betacellulin (BTC) mRNAs were measured by real-time RT-PCR. RESULTS: The proportion of cells in S-phase was 7.5% prior to hCG and did not decline until 24 h after hCG (3.1%). EGFR protein and BTC mRNA did not change following hCG, whereas AREG and EREG mRNA increased starting at 3 and 12 h post-hCG, respectively, and remained elevated thereafter. CONCLUSIONS: Cell cycle transit of macaque granulosa cells does not change until 24 h after an ovulatory stimulus, whereas the EGF-like ligands EREG and AREG are increased rapidly. This suggests that luteinizing granulosa cells are refractory to mitogenic stimulation by EGFR ligands.
BACKGROUND: This study seeks to clarify cell cycle dynamics of granulosa cells following hCG and elucidate the expression of epidermal growth factor (EGF)-like ligands during luteinization. METHODS: Granulosa cells were obtained from rhesus macaques undergoing controlled ovarian stimulation protocols before or after an ovulatory hCG bolus. Cell cycle characteristics were determined by flow cytometry and levels of EGF receptor (EGFR), amphiregulin (AREG), epiregulin (EREG) and betacellulin (BTC) mRNAs were measured by real-time RT-PCR. RESULTS: The proportion of cells in S-phase was 7.5% prior to hCG and did not decline until 24 h after hCG (3.1%). EGFR protein and BTC mRNA did not change following hCG, whereas AREG and EREG mRNA increased starting at 3 and 12 h post-hCG, respectively, and remained elevated thereafter. CONCLUSIONS: Cell cycle transit of macaque granulosa cells does not change until 24 h after an ovulatory stimulus, whereas the EGF-like ligands EREG and AREG are increased rapidly. This suggests that luteinizing granulosa cells are refractory to mitogenic stimulation by EGFR ligands.
Authors: Fuhua Xu; Richard L Stouffer; Jörg Müller; Jon D Hennebold; Jay W Wright; Alistair Bahar; Gabriele Leder; Michaele Peters; Melissa Thorne; Micaela Sims; Tim Wintermantel; Bernhard Lindenthal Journal: Mol Hum Reprod Date: 2010-10-29 Impact factor: 4.025
Authors: Jenna K Nyholt de Prada; Young S Lee; Keith E Latham; Charles L Chaffin; Catherine A VandeVoort Journal: Am J Physiol Endocrinol Metab Date: 2009-03-10 Impact factor: 4.310
Authors: Young S Lee; Catherine A VandeVoort; John P Gaughan; Uros Midic; Zoran Obradovic; Keith E Latham Journal: Am J Physiol Endocrinol Metab Date: 2011-04-12 Impact factor: 4.310
Authors: Charles L Chaffin; Young S Lee; Catherine A VandeVoort; Bela G Patel; Keith E Latham Journal: Endocrinology Date: 2012-09-24 Impact factor: 4.736