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Epidermal growth factor regulation of connexin 43 in cultured granulosa cells from preantral rabbit follicles
Author(s) -
Kennedy Katie L.,
Floyd Anthony A.,
Clarkson Alison M.,
Lee Vaughan H.
Publication year - 2003
Publication title -
molecular reproduction and development
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.745
H-Index - 105
eISSN - 1098-2795
pISSN - 1040-452X
DOI - 10.1002/mrd.10219
Subject(s) - biology , epidermal growth factor , connexin , granulosa cell , western blot , ovarian follicle , folliculogenesis , medicine , endocrinology , follicular phase , gap junction , cell culture , microbiology and biotechnology , andrology , gene , embryogenesis , intracellular , embryo , biochemistry , genetics
Connexin 43 (Cx43), a gap junction protein expressed in differentiated granulosa cells, is necessary for normal follicular development. Cx43 expression and regulation by epidermal growth factor (EGF) were characterized in immature rabbit granulosa cells. Cx43 mRNA was expressed in the granulosa cells of primary follicles, but was undetectable in primordial follicles. Abundant expression of Cx43 mRNA was maintained in the granulosa cells of growing follicles through maturity. Granulosa cells were isolated from early preantral follicles and maintained in monolayer cultures for 72 hr. After the first 24 hr of culture, they were maintained for 48 hr in serum‐free medium supplemented with 0, 1, 5, or 10 ng/ml of mouse EGF. Granulosa cell proteins were isolated, solubilized, and evaluated for Cx43 by Western blot analysis using antibodies to rat Cx43. Relative amounts of Cx43 protein (both phosphorylated and nonphosphorylated) were increased ( P < 0.05) by EGF in a dose‐dependent manner. Northern blot analysis of RNA from cultured granulosa cells demonstrated increased amounts of Cx43 mRNA in the EGF treated cultures (10 ng EGF/ml) relative to controls ( P < 0.03). In summary, Cx43 gap junctions are synthesized in granulosa cells following the onset of folliculogenesis in vivo and their expression is enhanced by EGF in vitro. Mol. Reprod. Dev. 64: 61–69, 2003. © 2003 Wiley‐Liss, Inc.