Matches in SemOpenAlex for { <https://semopenalex.org/work/W1984673721> ?p ?o ?g. }
- W1984673721 endingPage "834" @default.
- W1984673721 startingPage "827" @default.
- W1984673721 abstract "The preovulatory GnRH/LH surge in the ewe is stimulated by a rise in the circulating estradiol concentration that occurs in conjunction with preovulatory ovarian follicle development. In the presence of high levels of progesterone, such as during the luteal phase of the estrous/menstrual cycle, the stimulatory effects of elevated estradiol on GnRH/LH secretion are blocked. Recent work in the ewe has shown that a relatively short period of estradiol exposure can stimulate a GnRH/LH surge that begins after estrogenic support has been removed. This result suggests that surge generation is characterized by an estradiol-dependent period (during which the signal is read) and an estradiol-independent period (during which a cascade of neuronal events transmits the stimulatory signal to the GnRH neurosecretory system, which releases a surge of GnRH). In this series of studies, we addressed the hypothesis that progesterone can block transmission of the stimulatory estradiol signal after it has been read. Nine ovariectomized ewes were run through repeated artificial estrous cycles by sequential addition and removal of exogenous steroids. In study one, ewes received three treatments in a randomized cross-over design. Exposure to a follicular phase estradiol concentration for 10 h (positive control treatment) stimulated an LH surge in all ewes, as determined in hourly jugular blood samples. Maintenance of luteal phase progesterone concentrations throughout the artificial follicular phase (2 x CIDR-G devices, negative control) blocked the stimulatory effects of a 10-h estradiol signal, and no ewes that received this treatment expressed an LH surge. In the experimental group, exposure to luteal phase levels of progesterone, during the period after the surge generating system had been activated by estradiol, blocked the LH surge in six of nine ewes. This result demonstrates that progesterone can block the surge, even when applied after the surge-generating system has been activated and, therefore, that it inhibits either the transmission of the estradiol signal and/or the release of the GnRH/LH surge. In study 2, we assessed whether sensitivity to the inhibitory effects of progesterone was confined to a specific stage of the transmission of the estradiol signal. Eight ewes were exposed to four treatments, over successive artificial estrous cycles. Positive and negative controls were similar to those described in Study 1, except the duration of the stimulatory estradiol signal was reduced to 8 h. The two experimental groups consisted of an EARLY P (progesterone) treatment, in which progesterone was given from hours 8-13 after estradiol insertion (immediately after estradiol removal), and a LATE P treatment, in which progesterone was given from hours 13-18 (immediately before LH surge secretion). As expected, LH surges were stimulated and blocked, in response to the positive and negative controls, respectively. Whereas the EARLY P treatment blocked the LH surge in seven of eight ewes, the LATE P treatment was only successful in inhibiting a surge in one of eight animals. This result demonstrates that progesterone can block the estradiol-induced surge-generating signal soon after the onset of signal transmission (immediately after estradiol removal) but not during the later stages of signal transmission (at the time of GnRH/LH surge onset)." @default.
- W1984673721 created "2016-06-24" @default.
- W1984673721 creator A5032236142 @default.
- W1984673721 creator A5033803349 @default.
- W1984673721 creator A5037346777 @default.
- W1984673721 creator A5050826731 @default.
- W1984673721 creator A5029664021 @default.
- W1984673721 date "1999-02-01" @default.
- W1984673721 modified "2023-09-26" @default.
- W1984673721 title "Progesterone Can Block Transmission of the Estradiol-Induced Signal for Luteinizing Hormone Surge Generation during a Specific Period of Time Immediately after Activation of the Gonadotropin-Releasing Hormone Surge-Generating System<sup>1</sup>" @default.
- W1984673721 cites W1541228389 @default.
- W1984673721 cites W1978574139 @default.
- W1984673721 cites W1991546652 @default.
- W1984673721 cites W1992225214 @default.
- W1984673721 cites W1996046925 @default.
- W1984673721 cites W1996141079 @default.
- W1984673721 cites W1996613370 @default.
- W1984673721 cites W2005923380 @default.
- W1984673721 cites W2011110265 @default.
- W1984673721 cites W2014287820 @default.
- W1984673721 cites W2018045740 @default.
- W1984673721 cites W2018664770 @default.
- W1984673721 cites W2023717058 @default.
- W1984673721 cites W2026278013 @default.
- W1984673721 cites W2046630602 @default.
- W1984673721 cites W2056740997 @default.
- W1984673721 cites W2057129793 @default.
- W1984673721 cites W2063645101 @default.
- W1984673721 cites W2068812916 @default.
- W1984673721 cites W2070625108 @default.
- W1984673721 cites W2078032554 @default.
- W1984673721 cites W2078951282 @default.
- W1984673721 cites W2079486998 @default.
- W1984673721 cites W2080182601 @default.
- W1984673721 cites W2142400691 @default.
- W1984673721 cites W2167747681 @default.
- W1984673721 cites W2394995650 @default.
- W1984673721 doi "https://doi.org/10.1210/endo.140.2.6490" @default.
- W1984673721 hasPubMedId "https://pubmed.ncbi.nlm.nih.gov/9927312" @default.
- W1984673721 hasPublicationYear "1999" @default.
- W1984673721 type Work @default.
- W1984673721 sameAs 1984673721 @default.
- W1984673721 citedByCount "49" @default.
- W1984673721 countsByYear W19846737212012 @default.
- W1984673721 countsByYear W19846737212015 @default.
- W1984673721 countsByYear W19846737212016 @default.
- W1984673721 countsByYear W19846737212017 @default.
- W1984673721 countsByYear W19846737212018 @default.
- W1984673721 countsByYear W19846737212019 @default.
- W1984673721 countsByYear W19846737212020 @default.
- W1984673721 countsByYear W19846737212021 @default.
- W1984673721 countsByYear W19846737212022 @default.
- W1984673721 countsByYear W19846737212023 @default.
- W1984673721 crossrefType "journal-article" @default.
- W1984673721 hasAuthorship W1984673721A5029664021 @default.
- W1984673721 hasAuthorship W1984673721A5032236142 @default.
- W1984673721 hasAuthorship W1984673721A5033803349 @default.
- W1984673721 hasAuthorship W1984673721A5037346777 @default.
- W1984673721 hasAuthorship W1984673721A5050826731 @default.
- W1984673721 hasBestOaLocation W19846737211 @default.
- W1984673721 hasConcept C126322002 @default.
- W1984673721 hasConcept C134018914 @default.
- W1984673721 hasConcept C143228043 @default.
- W1984673721 hasConcept C185592680 @default.
- W1984673721 hasConcept C187785154 @default.
- W1984673721 hasConcept C1998276 @default.
- W1984673721 hasConcept C2777164284 @default.
- W1984673721 hasConcept C2777702977 @default.
- W1984673721 hasConcept C2778324911 @default.
- W1984673721 hasConcept C2778575703 @default.
- W1984673721 hasConcept C2778782382 @default.
- W1984673721 hasConcept C2778894405 @default.
- W1984673721 hasConcept C71315377 @default.
- W1984673721 hasConcept C71924100 @default.
- W1984673721 hasConcept C8264082 @default.
- W1984673721 hasConcept C86803240 @default.
- W1984673721 hasConceptScore W1984673721C126322002 @default.
- W1984673721 hasConceptScore W1984673721C134018914 @default.
- W1984673721 hasConceptScore W1984673721C143228043 @default.
- W1984673721 hasConceptScore W1984673721C185592680 @default.
- W1984673721 hasConceptScore W1984673721C187785154 @default.
- W1984673721 hasConceptScore W1984673721C1998276 @default.
- W1984673721 hasConceptScore W1984673721C2777164284 @default.
- W1984673721 hasConceptScore W1984673721C2777702977 @default.
- W1984673721 hasConceptScore W1984673721C2778324911 @default.
- W1984673721 hasConceptScore W1984673721C2778575703 @default.
- W1984673721 hasConceptScore W1984673721C2778782382 @default.
- W1984673721 hasConceptScore W1984673721C2778894405 @default.
- W1984673721 hasConceptScore W1984673721C71315377 @default.
- W1984673721 hasConceptScore W1984673721C71924100 @default.
- W1984673721 hasConceptScore W1984673721C8264082 @default.
- W1984673721 hasConceptScore W1984673721C86803240 @default.
- W1984673721 hasIssue "2" @default.
- W1984673721 hasLocation W19846737211 @default.
- W1984673721 hasLocation W19846737212 @default.
- W1984673721 hasOpenAccess W1984673721 @default.
- W1984673721 hasPrimaryLocation W19846737211 @default.
- W1984673721 hasRelatedWork W1966445265 @default.