title: Suppression of ovulation by a synthetic progestin in the capuchin monkey.
abstract: BACKGROUND
  From the limited research in New World monkeys it is not clear whether they are as sensitive to the antiovulatory effects of synthetic progestins as noted in human beings. We examined whether levonorgestrel prevented ovulation in the capuchin monkey.
  
  
  METHODS
  Cebus apella monkeys were treated orally with two doses of 2 mg of levonorgestrel, 8-9 hours apart, in four periovulatory stages assessed by laparoscopy.
  
  
  RESULTS
  Levonorgestrel-induced luteinization of the follicle prevented oocyte release up to 8 hours before ovulation. Unhealthy oocytes were recovered from 46% of unruptured follicles. Luteal progesterone was reduced by 55%, 35%, and 25% according to when levonorgestrel was given -2, -1, and 0 day from estradiol peak respectively.
  
  
  CONCLUSIONS
  The capuchin monkey, a neotropical primate in which progesterone circulates at levels much higher than in Old World primates and human beings, is sensitive to the antiovulatory effects of synthetic progestins.
authors.affiliation: Centro de Investigación en Reproducción Humana y Experimental, Instituto Universitario CEMIC, Buenos, Aires, Argentina. cnagle@cemic.edu.ar
authors.forename: Carlos A
authors.initials: CA
authors.lastname: Nagle
authors.forename: Monica M
authors.initials: MM
authors.lastname: Lahoz
authors.forename: Maria M
authors.initials: MM
authors.lastname: Porta
authors.forename: Marta
authors.initials: M
authors.lastname: Torres
authors.forename: Teresita
authors.initials: T
authors.lastname: Manzur
authors.forename: Zulema
authors.initials: Z
authors.lastname: Farinati
mesh_terms: D000818:Animals; D002428:Cebus; D003280:Contraceptives, Oral, Synthetic / Q000494:pharmacology*; D003338:Corpus Luteum / Q000187:drug effects; D004958:Estradiol / Q000097:blood; D005260:Female; D010535:Laparoscopy; D016912:Levonorgestrel / Q000494:pharmacology*; D006080:Ovarian Follicle / Q000187:drug effects*; D034445:Ovulation Inhibition / Q000097:blood; D011374:Progesterone / Q000097:blood
chemical_list: D003280:Contraceptives, Oral, Synthetic; D011374:Progesterone; D004958:Estradiol; D016912:Levonorgestrel