Skip Navigation

This Article
Right arrow Full Text (PDF )
Right arrow Submit a response
Right arrow Alert me when this article is cited
Right arrow Alert me when eLetters are posted
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Alert me to new issues of the journal
Right arrow Add to My Personal Archive
Right arrow Download to citation manager
Right arrowRequest Permissions
Google Scholar
Right arrow Articles by Ortmann, O.
Right arrow Articles by Emons, G.
Right arrow Search for Related Content
PubMed
Right arrow Articles by Ortmann, O.
Right arrow Articles by Emons, G.
Social Bookmarking
Add to CiteULike   Add to Connotea   Add to Del.icio.us  
What's this?

Human Reproduction, Vol. 9, No. suppl_1, pp. 53-62, 1994
© 1994 European Society of Human Reproduction and Embryology

Modulatory action of progesterone and progesterone antagonists on hypothalamic–pituitary function

O. Ortmann1,2,3, K.J. Catt3, K.-D. Schulz1 and G. Emons1,2

1 Departments of Obstetrics and Gynecology, Philipps-University Marburg Pilgrimstein 3, 35033 Marburg, Germany 2 Medical University of Lübeck Ratzeburger Allee 160, 23538 Lübeck, Germany 3 Endocrinology and Reproduction Research Branch, NICHD, National Institutes of Health Bethesda, MD 20892, USA

The ability of ovarian steroids to sensitize and desensitize the pituitary gonadotroph to hypothalamic gonadotrophin-releasing hormone (GnRH) is essential for their modulatory actions on gonadotrophin secretion. The time-dependent actions of progesterone on GnRH-stimulated gonadotrophin secretion from cultured pituitary cells obtained from female rats were examined. Progesterone induced an acute stimulatory effect on luteinizing hormone (LH) and follicle stimulating hormone (FSH) secretion in cell perifusion studies, from as early as 50 min after the onset of progesterone treatment. Long-term incubation (52 h) of pituitary cells in static culture reduced the responsiveness of the gonadotroph to GnRH. The antiprogestins RU486, ZK 98.299, and ZK 98.734 blocked both the acute facilitatory and the long-term inhibitory action of progesterone. In the absence of progesterone, the antiprogestins per se induced marked inhibitory and stimulatory effects on GnRH-stimulated LH secretion. In brief, short-term treatment of non oestrogen-primed cells with antiprogestins was ineffective (ZK compounds) or reduced LH secretion (RU486), while long-term treatment was stimulatory. Oestrogen-primed cells exerted exclusively inhibitory effects on GnRH-induced LH secretion. In conclusion, antiprogestins are effective antagonists of progesterone actions in the gonadotrophin. However, they exert diverse actions on gonadotrophin secretion in the absence of progesterone, which might interfere with their antagonistic properties.

Key words: antiprogestins/hyothalamus/LH secretion/pituitary/progesterone


Add to CiteULike CiteULike   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us    What's this?




Disclaimer: Please note that abstracts for content published before 1996 were created through digital scanning and may therefore not exactly replicate the text of the original print issues. All efforts have been made to ensure accuracy, but the Publisher will not be held responsible for any remaining inaccuracies. If you require any further clarification, please contact our Customer Services Department.