EFFECTS OF RU486 ON THE OVARIAN RESPONSE OF IMMATURE RATS TO PREGNANT MARES SERUM GONADOTROPIN OR DIETHYLSTILBESTROL

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dc.contributor.authorFORCELLEDO, ML
dc.contributor.authorLEIVA, L
dc.contributor.authorCROXATTO, HB
dc.date.accessioned2025-01-23T19:21:30Z
dc.date.available2025-01-23T19:21:30Z
dc.date.issued1994
dc.description.abstractThe purpose of this study was to further investigate the role of progesterone in follicular development induced by pregnant mare serum gonadotrophin (PMSG) or diethylstilbestrol (DES), in pre-pubertal rats, using RU486 to prevent the receptor-mediated actions of progesterone. Intact or hypophysectomized 26-day-old rats received either a single injection of 10 IU PMSG i.p., or 2 mg DES s.c. daily for 3 days, with or without 0.8 mg RU486 s.c. daily for 3 days. Groups of rats were killed 51-96 h after the first injection. RU486 significantly increased the ovarian weight gain, the ovarian and circulating concentrations of progesterone, the concentrations of immunoreactive and bioactive LH and the number of ovulated oocytes in intact rats. RU486 did not affect the ovarian weight increase induced by PMSG or the ovulatory response following PMSG plus human chorionic gonadotrophin (HCG) in rats hypophysectomized 24 h before initiating treatment or in intact rats where ovulation was blocked with chlorpromazine. The ovarian weight gain, the development of antral follicles and the increments in tissue and plasma progesterone concentrations and luteinizing hormone (LH) plasma concentrations elicited by DES in intact rats, were further increased by concomitant treatment with RU486, whereas the ovarian weight increase and antral follicle development induced by DES were completely inhibited by RU486 in hypophysectomized rats. Follicles stimulated to grow by DES plus RU486, but not by DES alone, were capable of ovulating in response to HCG. These results show that ovarian growth and follicular development induced by exogenous gonadotrophin or oestrogen in the immature rat are enhanced by RU486 and that this synergistic effect of the progesterone receptor blocker is either pituitary-mediated or requires the permissive action of a pituitary factor. Overall they support a negative effect of progesterone on follicular development in the rat.
dc.fuente.origenWOS
dc.identifier.eissn1460-2350
dc.identifier.issn0268-1161
dc.identifier.urihttps://repositorio.uc.cl/handle/11534/98789
dc.identifier.wosidWOS:A1994MU98200005
dc.issue.numero1
dc.language.isoen
dc.pagina.final31
dc.pagina.inicio24
dc.revistaHuman reproduction
dc.rightsacceso restringido
dc.subjectANTIPROGESTIN
dc.subjectFOLLICULAR DEVELOPMENT
dc.subjectOVULATION
dc.subjectPROGESTERONE
dc.subjectRAT
dc.subject.ods03 Good Health and Well-being
dc.subject.odspa03 Salud y bienestar
dc.titleEFFECTS OF RU486 ON THE OVARIAN RESPONSE OF IMMATURE RATS TO PREGNANT MARES SERUM GONADOTROPIN OR DIETHYLSTILBESTROL
dc.typeartículo
dc.volumen9
sipa.indexWOS
sipa.trazabilidadWOS;2025-01-12
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