Abstract
1. The ovulation response to electrical stimulation of the median eminence, or to the intrapituitary infusion of median eminence extract, was observed in control rabbits and animals pre-treated with chlormadinone acetate.
2. Chlormadinone acetate pre-treatment did not significantly reduce the proportion of rabbits ovulating in response to electrical stimulation. However, there was a significant reduction in the average number of ruptured follicles when compared with the animals in the control group.
3. Chlormadinone acetate pre-treatment significantly reduced the proportion of animals ovulating in response to the intrapituitary infusion of median eminence extract as compared with the control series. However, there was no significant reduction in the average number of ruptured follicles (in those rabbits that ovulated) when compared with the control groups.
4. Chlormadinone acetate pre-treatment produced no significant effect upon either the proportion of animals ovulating, or the average number of ruptured follicles, following I.V. injection of 50 μg LH.
5. The conclusion drawn is that chlormadinone acetate blocks copulattion-induced ovulation in the rabbit by action at a site in the central nervous system located above the median eminence. The possible effects of chlormadinone acetate upon the secretion of FSH, the pituitary sensitivity to releasing factors and the ovarian sensitivity to LH are discussed.
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Selected References
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- CAMPBELL H. J., FEUER G., HARRIS G. W. THE EFFECT OF INTRAPITUITARY INFUSION OF MEDIAN EMINENCE AND OTHER BRAIN EXTRACTS ON ANTERIOR PITUITARY GONADOTROPHIC SECRETION. J Physiol. 1964 Apr;170:474–486. doi: 10.1113/jphysiol.1964.sp007344. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Döcke F., Dörner G., Voigt K. H. A possible mechanism of the ovulation-inhibiting effect of chlormadinone acetate in the rat. J Endocrinol. 1968 Jul;41(3):353–362. doi: 10.1677/joe.0.0410353. [DOI] [PubMed] [Google Scholar]
- Exley D., Gellert R. J., Harris G. W., Nadler R. D. The site of action of 'chlormadinone acetate' (6-chloro-delta 6-dehydro-17 alpha-acetoxyprogesterone) in blocking ovulation in the mated rabbit. J Physiol. 1968 Apr;195(3):697–714. doi: 10.1113/jphysiol.1968.sp008483. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Hilliard J., Croxatto H. B., Hayward J. N., Sawyer C. H. Norethindrone blockade of LH release to intrapituitary infusion of hypothalamic extract. Endocrinology. 1966 Aug;79(2):411–419. doi: 10.1210/endo-79-2-411. [DOI] [PubMed] [Google Scholar]
- KANEMATSU S., SAWYER C. H. BLOCKADE OF OVULATION IN RABBITS BY HYPOTHALMIC IMPLANTS OF NORETHINDRONE. Endocrinology. 1965 Apr;76:691–699. doi: 10.1210/endo-76-4-691. [DOI] [PubMed] [Google Scholar]
- Kawakami M., Sawyer C. H. Effects of sex hormones and antifertility steroids in brain thresholds in the rabbit. Endocrinology. 1967 May;80(5):857–871. doi: 10.1210/endo-80-5-857. [DOI] [PubMed] [Google Scholar]