title: Epidermal growth factor and transforming growth factor-beta modulation of follicle-stimulating hormone-induced deoxyribonucleic acid synthesis in hamster preantral and early antral follicles.
abstract: The interactions of epidermal growth factor (EGF) and transforming growth factor-beta (TGF-beta) in modulating FSH-induced follicular DNA synthesis were studied in isolated intact preantral (stages 1-6) and early antral (stage 7) ovarian follicles from adult hamsters. Follicles were exposed in vitro for 24 h to FSH (100 ng), EGF (50 ng), TGF-beta 1 (1-10 ng), or TGF-beta 2 (1-10 ng), either alone or in combination. The rate of DNA synthesis was assessed by measuring the incorporation of [3H]thymidine into follicular DNA. Both EGF and FSH significantly stimulated follicular DNA synthesis compared with that in controls. Both isoforms of TGF-beta significantly increased follicular [3H]thymidine incorporation in a dose-dependent manner; the effect was greater for small preantral follicles, such as those of stages 1-4. Interestingly, TGF-beta significantly inhibited EGF-induced follicular DNA synthesis, but the rates of DNA synthesis for most of the stages were still higher than that of the control follicles. Specificity of the TGF-beta action on follicular DNA synthesis was evident from the ability of isoform-specific anti-TGF-beta antibodies to neutralize the effect. These antibodies also reversed the TGF-beta inhibition of EGF-induced DNA synthesis. Surprisingly, although TGF-beta attenuated EGF-induced DNA synthesis, it synergized with FSH to stimulate follicular DNA synthesis. Interestingly, FSH-induced DNA synthesis remained unaffected by the anti-TGF-beta antibodies, indicating that TGF-beta may not mediate FSH action on follicular DNA synthesis. These studies suggest that a critical interaction of EGF and TGF-beta modulates granulosa cell proliferation during folliculogenesis in the hamster.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Department of Obstetrics and Gynecology, University of Nebraska Medical Center, Omaha 68198.
authors.forename: S K
authors.initials: SK
authors.lastname: Roy
mesh_terms: D000818:Animals; D002455:Cell Division / Q000187:drug effects; D006224:Cricetinae; D004247:DNA / Q000096:biosynthesis*; D004347:Drug Interactions; D004815:Epidermal Growth Factor / Q000008:administration & dosage / Q000494:pharmacology; D005260:Female; D005640:Follicle Stimulating Hormone / Q000008:administration & dosage / Q000494:pharmacology; D066298:In Vitro Techniques; D007700:Kinetics; D008647:Mesocricetus; D006080:Ovarian Follicle / Q000187:drug effects* / Q000378:metabolism* / Q000502:physiology; D016212:Transforming Growth Factor beta / Q000008:administration & dosage / Q000494:pharmacology*
chemical_list: D016212:Transforming Growth Factor beta; D004815:Epidermal Growth Factor; D005640:Follicle Stimulating Hormone; D004247:DNA