Estradiol-17 beta stimulates DNA synthesis in rat granulosa cells: action mediated by transforming growth factor-beta.
Estradiol-17 beta is a mitogen in vivo for the proliferation of granulosa cells in the rat ovary. In this study we have shown that estradiol-17 beta acts on cultures of immature rat granulosa cells to stimulate DNA synthesis. DNA synthesis stimulated by estradiol-17 beta was enhanced by FSH. We have shown previously that transforming growth factor-beta (TGF-beta) stimulates DNA synthesis in rat granulosa cells in vitro and that this effect is augmented by FSH. The mitogenic action of estradiol-17 beta was mediated, at least in part, by a TGF-beta-like factor since in the presence of a neutralizing antibody to TGF-beta, DNA synthesis was attenuated. This conclusion was further supported by the novel finding that estradiol-17 beta stimulated the secretion of a TGF-beta-like factor by rat granulosa cells in culture. In summary, the evidence suggests that the actions of estradiol-17 beta and TGF-beta on DNA synthesis are interrelated, and that a TGF-beta-like factor mediates the mitogenic effects of estradiol-17 beta on rat granulosa cells.
Bendell
J J
JJ
Banting and Best Department of Medical Research, University of Toronto, Ontario, Canada.
Dorrington
J
J
D000818:Animals; D000906:Antibodies / Q000276:immunology; D003470:Culture Media; D004247:DNA / Q000096:biosynthesis*; D004958:Estradiol / Q000494:pharmacology*; D005260:Female; D006107:Granulosa Cells / Q000378:metabolism*; D051381:Rats; D013936:Thymidine / Q000378:metabolism; D016212:Transforming Growth Factor beta / Q000276:immunology / Q000378:metabolism / Q000502:physiology*
D000906:Antibodies; D003470:Culture Media; D016212:Transforming Growth Factor beta; D004958:Estradiol; D004247:DNA; D013936:Thymidine