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Semin Reprod Med 2009; 27(1): 052-061
DOI: 10.1055/s-0028-1108010
© Thieme Medical Publishers

Epidermal Growth Factor-Like Growth Factors in the Follicular Fluid: Role in Oocyte Development and Maturation

Minnie Hsieh1 , A. Musa Zamah1 , Marco Conti1
  • 1Department of Obstetrics, Gynecology and Reproductive Sciences and the Center for Reproductive Sciences, University of California, San Francisco, San Francisco, California
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Publication History

Publication Date:
05 February 2009 (online)

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ABSTRACT

The growth and maturation of the ovarian follicle requires the coordinate function of somatic cells and the oocyte. Over the past three decades, numerous growth factors involved in the bidirectional signals between the somatic and germ cells have been identified. A possible function of epidermal growth factor (EGF) signaling at selected stages of follicle maturation had been proposed early on and is supported by many observations of in vitro effects of this growth factor on steroidogenesis, oocyte maturation, and cumulus expansion. However, attempts to link EGF levels in the follicular fluid with the state of follicle and oocyte maturation have been inconclusive. More recently, data generated using mouse genetic models perturbing ovulation and fertility indicate that EGF-like growth factors, rather than EGF itself, accumulate in the follicle at the time of ovulation. EGF-like growth factor mRNA is regulated by the luteinizing hormone surge, and corresponding proteins are detected in the follicle. The EGF-like growth factors amphiregulin, epiregulin, and betacellulin are potent stimulators of oocyte maturation and cumulus expansion, and perturbation of this EGF network in vivo impairs ovulation. Similar findings in species other than the mouse confirm an important physiological role for this network at the time of ovulation. Whether this network also plays a critical role in humans and whether it can be used as a biological marker of follicle development or for the improvement of fertility remains to be determined. This review summarizes the most recent findings on the EGF network during ovulation and the potential clinical applications of manipulating this intercellular communication pathway in the control of fertility.

KEYWORDS

Epidermal growth factor (EGF) - EGF-like factors - oocyte - follicular fluid