étudie l’effet de la DHEA sur l’axe hypothalamo-hypophyso-ovarien Comme la . treatment results in suppression of the. hypothalamo-pituitary ovarian axis. Effet hypothalamo-hypophysaire: les antiprogestatifs ont aussi des effets plus ou moins Effets ovariens: si l’effet ovarien direct du RU est éliminé dans la qui ont des activités freinatrices sur l’axe hypothalamo-hypophyso-gonadique. Rôle de la signalisation des kisspeptines dans la régulation de l’axe nécessaires à l’activation centrale de l’axe hypothalamo-hypophyso-ovarien à la puberté.
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Kisspeptins are a series of overlapping peptides encoded by the Kiss1 gene that are required for central activation of the hypothalamic-pituitary-ovarian axis at puberty.
Mutations that interfere with kisspeptin signalling prevent normal pubertal development in humans and mice. Mutations in the hypophjso receptor GPR54, cause infertility and hypogonadotrophic hypogonadism in hypopyyso. The failure of the Gpr54 and Kiss1 mutant mice to ovulate has led to the suggestion that kisspeptin signalling may be required for the preovulatory luteinizing hormone LH surge.
Although kisspeptin signalling has been shown to have an important central role in regulating the physiology of the ovary, the expression profile of Kiss1 and Gpr54 suggests that they may also have direct functions in the ovary and the placenta.
Mutant females do not show normal estrous cycling or ovulation. The uteri are thread like and the ovaries significantly smaller than normal with no corpora lutea. The failure of the Gpr54 and Kiss1 mutant mice to ovulate has led to the suggestion that kisspeptin signalling may be required for the preovulatory surge.
Several lines of data support this hypothesis. Kiss1 is expressed in the AVPV region of the hypothalamus; an area known to regulate the pre-ovulatory LH surge in rodents.
Kiss1 expression in AVPV neurons is increased in response to estradiol treatment and Kiss1 neurons are activated as indicated by c-fos induction.
Expression of KiSS-1 in rat ovary: KiSS-1 in the mammalian ovary: EE Click here to see the Library ]. Moderate kisspeptin is also found in regressing corpora lutea particularly in steroidogenic cells.
Similarly, KISS1R ovariwn has been localized to the thecal layer xxe pre-ovulatory follicles and steroidogenic luteal cells of the corpus luteum.
We have found that mutant mice that have been induced to ovulate by injection of gonadotrophic hormones have lower progesterone levels than wild-type mice and we are investigating whether this represents an intrinsic defect in the corpus luteum. Dramatic elevation of plasma metastin concentrations in human pregnancy: Expression of KISS1R by the highly invasive cytotrophoblast cells has led to the suggestion that these proteins may regulate placental invasion but the birth of Gpr54 and Kiss1 mutant mice indicates that placentation can take place in the absence of kisspeptin signalling from the fetal part of the placenta.
To investigate the effect that loss of both maternal and fetal kisspeptin signalling may have on placental function, we are restoring fertility to the mutant mice by hormone treatment and trying to establish pregnancy. Initial data indicate that pregnancy is not maintained in the mutant mice past ace 7 of gestation even after progesterone treatment.
We are investigating the causes of this failure to maintain pregnancy. Regulator aaxe marker of ovarian function E. Journal page Archives Sommaire.
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The role of kisspeptin signalling in the regulation of the GnRH-gonadotrophin ovarian axis in mice. Outline Masquer le plan.
Kisspeptin signalling is required for activation of the reproductive axis at puberty. The role of kisspeptin signalling in the preovulatory LH surge.
The role of kisspeptin signalling in ovarian physiology and placentation.
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