title: Gonadotropin and steroid control of granulosa cell proliferation during the periovulatory interval in rhesus monkeys.
abstract: Progesterone produced in response to the midcycle gonadotropin surge is essential for ovulation and luteinization of the primate follicle. Because cell-cycle arrest is associated with the initiation of luteinization, this study was designed to determine the dynamics and regulation of granulosa cell proliferation by gonadotropin and progesterone during the periovulatory interval in the primate follicle. Granulosa cells or ovaries were obtained from macaques undergoing controlled ovarian stimulation either before (0 h) or as long as 36 h following the administration of an ovulatory hCG bolus with or without a 3beta-hydroxysteroid dehydrogenase inhibitor with or without a nonmetabolizable progestin. The percentage of cells staining positive for Ki-67, a nuclear marker for cell proliferation, decreased (P < 0.05) within 12 h of hCG administration in a steroid-independent manner. Levels of cyclin D2 and E mRNA did not decline during the periovulatory interval; however, cyclin B1 mRNA was reduced significantly by 12 h. Steroid depletion increased (P < 0.05) cyclin B1 mRNA at both 12 and 36 h post-hCG and was reversible by progestin replacement at 36 h. The cyclin-dependent kinase inhibitor p21(Cip1) was transiently increased 12 h post-hCG, whereas p27(Kip1) mRNA levels increased at 36 h in a steroid-independent fashion. These data suggest that a gonadotropin bolus inhibits mitosis in granulosa cells early (12 h) in the periovulatory interval, whereas progesterone may play a later, antiproliferative role in luteinized cells of primates.
authors.affiliation: Division of Reproductive Sciences, Oregon Regional Primate Research Center, 505 NW 185th St., Beaverton, OR 97006, USA.
authors.forename: C L
authors.initials: CL
authors.lastname: Chaffin
authors.forename: K M
authors.initials: KM
authors.lastname: Schwinof
authors.forename: R L
authors.initials: RL
authors.lastname: Stouffer
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000032:analysis; D018797:Cell Cycle Proteins / Q000235:genetics; D002455:Cell Division / Q000187:drug effects; D006063:Chorionic Gonadotropin / Q000494:pharmacology; D019926:Cyclin B / Q000235:genetics; D056744:Cyclin B1; D019927:Cyclin E / Q000235:genetics; D050759:Cyclin-Dependent Kinase Inhibitor p21; D050760:Cyclin-Dependent Kinase Inhibitor p27; D016213:Cyclins / Q000235:genetics; D005260:Female; D006062:Gonadotropins / Q000502:physiology*; D006107:Granulosa Cells / Q000737:chemistry / Q000166:cytology*; D019394:Ki-67 Antigen / Q000032:analysis; D008253:Macaca mulatta; D010060:Ovulation; D011374:Progesterone / Q000494:pharmacology; D012333:RNA, Messenger / Q000032:analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013256:Steroids / Q000502:physiology*; D025521:Tumor Suppressor Proteins / Q000235:genetics
chemical_list: D015415:Biomarkers; D018797:Cell Cycle Proteins; D006063:Chorionic Gonadotropin; D019926:Cyclin B; D056744:Cyclin B1; D019927:Cyclin E; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins; D006062:Gonadotropins; D019394:Ki-67 Antigen; D012333:RNA, Messenger; D013256:Steroids; D025521:Tumor Suppressor Proteins; D050760:Cyclin-Dependent Kinase Inhibitor p27; D011374:Progesterone