title: Nomegestrol acetate: steroid receptor transactivation profile in Chinese hamster ovary cells and ovulation inhibition in rat and monkey.
abstract: BACKGROUND
  Activity of nomegestrol acetate (NOMAC), levonorgestrel (LNG), drospirenone (DRSP), dienogest (DNG) and progesterone on human steroid receptor transactivation was investigated. Ovulation inhibition by NOMAC, LNG and progesterone was tested.
  
  
  METHODS
  The progestogen receptor profile was determined in Chinese hamster ovary cells transfected with human progesterone B (PRB), androgen, estrogen (ER(α) and ER(β)), glucocorticoid (GR) and mineralocorticoid (MR) receptors, respectively. Ovulation inhibition was tested in rats and monkeys.
  
  
  RESULTS
  Agonistic potency rankings for PRB were LNG=NOMAC≫progesterone≫DRSP>DNG. No antagonistic activity at PRB was observed. Only LNG had androgenic activity. Antiandrogenic potency rankings were LNG≫NOMAC>progesterone>DNG>DRSP. All agents were devoid of activity at ER(α), ER(β) and GR. Only progesterone, DRSP and LNG had anti-MR activity. The NOMAC dose inhibiting ovulation at 50% ranged from 0.14 mg/kg (monkey) to 1.25 to 5.0 mg/kg (rat).
  
  
  CONCLUSIONS
  Nomegestrol acetate is a selective progestogen and a potent inhibitor of ovulation in the rat and monkey.
authors.affiliation: Women's Health Department, Merck Research Laboratories, Oss, The Netherlands. harry.vandiepen@merck.com
authors.forename: Harry A
authors.initials: HA
authors.lastname: van Diepen
authors.forename: Tsang W
authors.initials: TW
authors.lastname: Lam
authors.forename: Cor W
authors.initials: CW
authors.lastname: Kuil
mesh_terms: D000818:Animals; D016466:CHO Cells; D006224:Cricetinae; D003412:Cricetulus; D005260:Female; D006801:Humans; D008252:Macaca fascicularis; D008535:Megestrol / Q000031:analogs & derivatives* / Q000494:pharmacology; D010060:Ovulation / Q000187:drug effects*; D045167:Progesterone Congeners / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D011987:Receptors, Steroid / Q000819:agonists* / Q000037:antagonists & inhibitors
chemical_list: D045167:Progesterone Congeners; D011987:Receptors, Steroid; C047637:nomegestrol; D008535:Megestrol