title: Anti-Müllerian hormone promotes pre-antral follicle growth, but inhibits antral follicle maturation and dominant follicle selection in primates.
abstract: What are the direct effects and physiological role of anti-Müllerian hormone (AMH) during primate follicular development and function at specific stages of folliculogenesis?
  
  
  
  AMH actions in the primate ovary may be stage-dependent, directly promoting pre-antral follicle growth while inhibiting antral follicle maturation and dominant follicle selection.
  
  
  
  AMH is expressed in the adult ovary, particularly in developing follicles. Studies in mice suggest that AMH suppresses pre-antral follicle growth in vitro, and inhibits primordial follicle recruitment and FSH-stimulated antral follicle steroidogenesis.
  
  
  
  For in vitro study, secondary follicles were isolated from ovaries of 12 rhesus macaques and cultured for 5 weeks. For in vivo study, intraovarian infusion was conducted on five monkeys for the entire follicular phase during two spontaneous menstrual cycles.
  
  
  
  For in vitro study, individual follicles were cultured in a 5% O2 environment, in alpha minimum essential medium supplemented with recombinant human FSH. Follicles were randomly assigned to treatments of recombinant human AMH protein or neutralizing anti-human AMH antibody (AMH-Ab). Follicle survival, growth, steroid production, steroidogenic enzyme expression, and oocyte maturation were assessed. For in vivo study, ovaries were infused with control vehicle or AMH-Ab during the follicular phase of the menstrual cycle. Cycle length, serum steroid levels, and antral follicle growth were evaluated.
  
  
  
  AMH exposure during culture weeks 0-3 (pre-antral stage) promoted, while AMH-Ab delayed, antrum formation of growing follicles compared with controls. AMH treatment during culture weeks 3-5 (antral stage) decreased (P < 0.05) estradiol (E2) production, as well as the mRNA expression of cytochrome P450 family 19 subfamily A polypeptide 1, by antral follicles relative to controls, whereas AMH-Ab increased (P < 0.05) follicular mRNA levels of the enzyme. Intraovarian infusion of AMH-Ab during the follicular phase of the menstrual cycle increased (P < 0.05) the average levels of serum E2 compared with those of the control cycles. Three of the five AMH-Ab-treated ovaries displayed multiple (n = 2-9) medium-to-large (2-8 mm) antral follicles at the mid-cycle E2 peak, whereas only one large (4-7 mm) antral follicle was observed in all monkeys during their control cycles. The average levels of serum progesterone were higher (P < 0.05) during the luteal phase of cycles following the AMH-Ab infusion relative to the vehicle infusion.
  
  
  
  The in vitro study of AMH actions on cultured individual macaque follicles was limited to the interval from the secondary to small antral stage. A sequential study design was used for in vivo experiments, which may limit the power of the study.
  
  
  
  The current study provides novel information on direct actions and role of AMH during primate follicular development, and selection of a dominant follicle by the late follicular phase of the menstrual cycle. We hypothesize that AMH acts positively on follicular growth during the pre-antral stage in primates, but negatively impacts antral follicle maturation, which is different from what is reported in the mouse model.
  
  
  
  NIH NICHD R01HD082208, NIH ORWH/NICHD K12HD043488 (BIRCWH), NIH OD P51OD011092 (ONPRC), Collins Medical Trust. There are no conflicts of interest.
  
  
  
  Not applicable.
authors.affiliation: Division of Reproductive & Developmental Sciences, Oregon National Primate Research Center, 505 NW 185th Avenue, Beaverton, OR 97006, USA xujin@ohsu.edu.
authors.forename: J
authors.initials: J
authors.lastname: Xu
authors.affiliation: Division of Reproductive & Developmental Sciences, Oregon National Primate Research Center, 505 NW 185th Avenue, Beaverton, OR 97006, USA.
authors.forename: C V
authors.initials: CV
authors.lastname: Bishop
authors.affiliation: Division of Reproductive & Developmental Sciences, Oregon National Primate Research Center, 505 NW 185th Avenue, Beaverton, OR 97006, USA.
authors.forename: M S
authors.initials: MS
authors.lastname: Lawson
authors.affiliation: OHSU-PSU School of Public Health, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, Portland, OR 97239, USA.
authors.forename: B S
authors.initials: BS
authors.lastname: Park
authors.affiliation: Division of Reproductive & Developmental Sciences, Oregon National Primate Research Center, 505 NW 185th Avenue, Beaverton, OR 97006, USA.
authors.forename: F
authors.initials: F
authors.lastname: Xu
mesh_terms: D000818:Animals; D054304:Anti-Mullerian Hormone / Q000097:blood / Q000276:immunology / Q000494:pharmacology*; D057134:Antibodies, Neutralizing / Q000494:pharmacology; D000072496:Cytochrome P450 Family 19 / Q000378:metabolism; D004958:Estradiol / Q000096:biosynthesis; D005260:Female; D008253:Macaca mulatta; D006080:Ovarian Follicle / Q000187:drug effects* / Q000254:growth & development; D011374:Progesterone / Q000097:blood; D012333:RNA, Messenger / Q000378:metabolism; D011897:Random Allocation; D046509:Tissue Culture Techniques
chemical_list: D057134:Antibodies, Neutralizing; D012333:RNA, Messenger; D011374:Progesterone; D004958:Estradiol; D054304:Anti-Mullerian Hormone; D000072496:Cytochrome P450 Family 19
keywords: anti-Müllerian hormone; antral follicle; follicle culture; intraovarian infusion; pre-antral follicle