Regulatory role of kit ligand-c-kit interaction and oocyte factors in steroidogenesis by rat granulosa cells

Tomoko Miyoshi, Fumio Otsuka, Eri Nakamura, Kenichi Inagaki, Kanako Ogura-Ochi, Naoko Yamauchi, Masaya Takeda, Hirofumi Makino

Research output: Contribution to journalArticlepeer-review

34 Citations (Scopus)


Although kit ligand (KL)-c-kit interaction is known to be critical for oogenesis and folliculogenesis, its role in ovarian steroidogenesis has yet to be elucidated. We studied the impact of KL-c-kit interaction in regulation of steroidogenesis using rat oocyte/granulosa cell co-culture. In the presence of oocytes, soluble KL suppressed FSH-induced estradiol production and aromatase mRNA expression without affecting FSH-induced progesterone production. The KL effect on steroidogenesis was interrupted by an anti-c-kit neutralizing antibody, suggesting that KL-c-kit interaction is involved in suppression of estrogen by granulosa cells through oocyte c-kit action. The cAMP-PKA pathway activity was not directly involved in the estrogen regulation by KL-c-kit action. It was of note that KL treatment increased the expression levels of oocyte-derived FGF-8, GDF-9 and BMP-6, while it reduced the expression levels of oocyte-derived BMP-15 in the oocyte-granulosa cell co-culture. Given the findings that FGF-8, but not GDF-9, BMP-6 or -15, suppressed FSH-induced estrogen production by granulosa cells, oocyte-derived FGF-8 is linked to suppression of FSH-induced estrogen production through the KL-c-kit interaction. Furthermore, the suppression of FSH-induced estrogen production by KL in the co-culture was reversed by a FGF receptor kinase inhibitor and the effect of the inhibitor was enhanced in combination with extracellular-domain protein of BMPRII, which interferes with BMP-15 and GDF-9 activities. Thus, the actions of endogenous oocyte factors including FGF-8 and BMP-15/GDF-9 were involved in the KL activity that inhibited FSH-induced estradiol production. Collectively, the results indicate that KL-c-kit interaction plays a role in estrogenic regulation through oocyte-granulosa cell communication.

Original languageEnglish
Pages (from-to)18-26
Number of pages9
JournalMolecular and cellular endocrinology
Issue number1
Publication statusPublished - Jul 6 2012


  • Bone morphogenetic protein (BMP)
  • C-kit
  • Granulosa cells
  • Kit ligand (KL)
  • Oocyte
  • Steroidogenesis

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Endocrinology


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