Influence of epidermal growth factor on mammalian oocyte maturation via tyrosine-kinase pathway

P. L. Lorenzo, I. K M Liu, J. C. Illera, R. A. Picazo, G. F. Carneiro, M. J. Illera, A. J. Conley, A. C. Enders, M. Illera

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16 Scopus citations


Epidermal growth factor (EGF) has been reported to promote different functions in mammalian ovaries, including oocyte maturation. The aim of the present study was to establish: that EGF influences oocyte maturation in ovine and equine, that a tyrosine kinase-dependent intracellular mechanism mediates EGF effect and, that EGF-R receptor is detectable in ovarian follicles by immunohistochemistry methods. Selected ovine and equine oocytes were aspirated from 2-5 mm (ovine) or 25 mm (equine) follicles and cultured in TCM 199 for 22 (ovine) or 36 hours (equine). They are then subjected to culture with EGF and two specific tyrosine-kinase inhibitors (TKIs, tyrphostins A-23 y A-47). Maturation was determined as the percentage of oocytes at metaphase II stage after culture. Treatments with EGF significantly increased incidences of metaphase II stage compared to controls (86.2% vs. 55% and 70.4% vs. 22.5% in ovine and equine oocytes, respectively). Tyrphostins A-23 and A-47 were effective in suppressing EGF-effect on oocytes. EGF-receptor was local-ized in follicles, being more prominent in cumulus and granulosa cells. These results confirm that EGF has a physiological role in the regulation of oocyte maturation via tyrosine-kinase pathway.

Original languageEnglish (US)
Pages (from-to)15-22
Number of pages8
JournalJournal of Physiology and Biochemistry
Issue number1
StatePublished - Mar 2001


  • EGF
  • Oocyte
  • Tyrosine-kinase inhibitors
  • Tyrphostins

ASJC Scopus subject areas

  • Biochemistry
  • Physiology


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