Role of gonadotrophins and progesterone in the regulation of morphological remodelling and atresia in the monkey peri-ovulatory follicle.
Peri-ovulatory progesterone plays an indispensable role in ovulation and luteinization, possibly by controlling tissue remodelling of the ovulatory follicle. This study was designed to evaluate gonadotrophin- versus progestin-mediated changes to the morphology of the follicle wall during luteinization. Ovaries were obtained from macaques undergoing ovarian stimulation either before (0 h) or up to 36 h following administration of an ovulatory human chorionic gonadotrophin (HCG) bolus with or without a 3beta-hydroxysteroid dehydrogenase inhibitor and a non-metabolisable progestin. Morphological changes occurred within 12 h of HCG in the theca, and around 24 h in the granulosa layer and basement membrane. Steroid depletion resulted in follicles that did not luteinize during the 36 h interval, or alternatively, those that exhibited premature luteinization by 12 h post-HCG. Progestin replacement restored normal morphology, although the presence of antral blood suggested acceleration of normal tissue remodelling. A proportion of pre-ovulatory follicles became atretic after the HCG bolus, although progestin treatment reduced the percentage of atretic follicles. Ovarian stimulation resulted in the development of multiple pre-ovulatory follicles which are heterogeneous in their response to the HCG bolus and local progestin action. Nevertheless, this model supports both anti-atretic and pro-differentiative actions of progesterone in promoting follicular health and remodelling during the development of the corpus luteum.
Chaffin
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CL
Division of Reproductive Sciences, Oregon Regional Primate Research Center, 505 NW 185th Ave, Beaverton, Oregon 97006, USA.
Stouffer
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RL
D015096:3-Hydroxysteroid Dehydrogenases / Q000037:antagonists & inhibitors; D000818:Animals; D006063:Chorionic Gonadotropin / Q000008:administration & dosage; D003338:Corpus Luteum / Q000502:physiology; D013196:Dihydrotestosterone / Q000031:analogs & derivatives* / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D005496:Follicular Atresia / Q000502:physiology*; D006065:Gonadotropins, Pituitary / Q000502:physiology*; D006107:Granulosa Cells / Q000187:drug effects; D006801:Humans; D007700:Kinetics; D008253:Macaca mulatta / Q000502:physiology*; D006080:Ovarian Follicle / Q000033:anatomy & histology* / Q000502:physiology; D010060:Ovulation / Q000502:physiology*; D010062:Ovulation Induction; D011374:Progesterone / Q000502:physiology*; D045167:Progesterone Congeners / Q000494:pharmacology; D011397:Promegestone / Q000494:pharmacology; D011994:Recombinant Proteins / Q000494:pharmacology; D013799:Theca Cells / Q000187:drug effects
D006063:Chorionic Gonadotropin; D004791:Enzyme Inhibitors; D006065:Gonadotropins, Pituitary; D045167:Progesterone Congeners; D011994:Recombinant Proteins; D013196:Dihydrotestosterone; D011374:Progesterone; D011397:Promegestone; D015096:3-Hydroxysteroid Dehydrogenases; C009954:trilostane