Effect of RU486 on ovarian progesterone production at pro-oestrus and during pregnancy: a possible dual regulation of the biosynthesis of progesterone.

摘要: Changes in progesterone production were analysed after intrabursal ovarian administration of the antiprogesterone RU486, mifepristone, rats at pro-oestrus and during pregnancy. RU486 was administered 09:00-10:00 h serum measured 8 treatment, except for those on days 3 12 pregnancy when steroid 4, 24 later. stimulates day 3-5 15-20 Conversely, treatment with antiprogestagen inhibits 7-14 gestation. The inhibition (day 12) or stimulation 19) induced by could be correlated simultaneous beta-hydroxysteroid dehydrogenase (3 beta-HSD) activity observed corpora lutea. A similar effect beta-HSD lutea obtained a specific antibody, indicating that is exerted through its action. On early injection did not modify prolactin LH concentrations, demonstrating have central stimulatory action 5 shifted to an inhibitory 7. Oestradiol 6 reversed 7, inducing response gestation.(ABSTRACT TRUNCATED AT 250 WORDS)