Matches in SemOpenAlex for { <https://semopenalex.org/work/W2097316923> ?p ?o ?g. }
Showing items 1 to 92 of
92
with 100 items per page.
- W2097316923 abstract "Administration of an estrogen challenge during the luteal phase, a time when progesterone concentrations are elevated, fails to elicit a gonadotropin-positive feedback response. The purpose of the present study was to determine if endogenous opiates are involved in the mechanism by which progesterone blocks the estrogen-induced gonadotropin surge in monkeys. To this end, rhesus monkeys in the luteal phase were pretreated with either saline or various regimens of nalmefene, a long-acting opiate antagonist, before being given an estrogen challenge. Three groups of animals were given nalmefene (10 mg, iv) every 12 h beginning 24, 48, or 96 h before an estrogen challenge and continued until 48 h after the start of the estrogen challenge. A fourth group received a continuous sc infusion of nalmefene (20 mg/day) via osmotic minipumps beginning 48 h in advance of the estrogen challenge. In a second experiment, monkeys in the follicular phase received progesterone implants at the time of an estrogen challenge and iv injections of nalmefene every 12 h for 48 h. Gonadotropin and steroid levels were monitored in both experiments by collecting blood samples by saphenous venipuncture at intervals of 6-12 h. The majority of luteal phase animals that were pretreated with saline were unresponsive to the estrogen challenge. Only 2 of 16 (12.5%) had an increase in LH concentrations that could be classified as a surge. Animals pretreated with iv nalmefene every 12 h beginning 48 h before the estrogen challenge exhibited a higher incidence of positive feedback responses (8 of 12 or 66.7%). A concomitant FSH surge was observed in 3 of these instances. However, when progesterone concentrations, which declined before the estrogen challenge in the nalmefene-treated group, were supplemented with exogenous progesterone, nalmefene failed to evoke any LH surges. Six of 8 animals that received nalmefene by sc infusion exhibited LH responses. However, the amplitude and duration of these LH responses were diminished, and no FSH responses were observed. Monkeys pretreated with nalmefene for either shorter (24 h) or longer (96 h) periods before the challenge were less responsive (0 responses out of 6 trials and 1 response out of 4 trials, respectively). Nalmefene was equally ineffective in preventing progesterone inhibition of the estradiol-induced LH surge in follicular phase animals (0 of 15 animals had LH surge). These results indicate that nalmefene antagonism of endogenous opiates does not enable estrogen to exert positive feedback effects on LH release when progesterone levels are high, such as during the luteal phase or after progesterone administration.(ABSTRACT TRUNCATED AT 400 WORDS)" @default.
- W2097316923 created "2016-06-24" @default.
- W2097316923 creator A5014144073 @default.
- W2097316923 creator A5053601910 @default.
- W2097316923 creator A5090058184 @default.
- W2097316923 date "1992-06-01" @default.
- W2097316923 modified "2023-09-27" @default.
- W2097316923 title "Progesterone inhibits the estrogen-induced gonadotropin surge in the rhesus monkey independent of endogenous opiates." @default.
- W2097316923 cites W1532801512 @default.
- W2097316923 cites W179769395 @default.
- W2097316923 cites W1965584350 @default.
- W2097316923 cites W1970076139 @default.
- W2097316923 cites W1972181075 @default.
- W2097316923 cites W1978086274 @default.
- W2097316923 cites W1982894122 @default.
- W2097316923 cites W1989917970 @default.
- W2097316923 cites W1992096020 @default.
- W2097316923 cites W1995339389 @default.
- W2097316923 cites W2000470884 @default.
- W2097316923 cites W2013520581 @default.
- W2097316923 cites W2027549819 @default.
- W2097316923 cites W2039100742 @default.
- W2097316923 cites W2056506664 @default.
- W2097316923 cites W2065722424 @default.
- W2097316923 cites W2068948430 @default.
- W2097316923 cites W2069348522 @default.
- W2097316923 cites W2069538424 @default.
- W2097316923 cites W2080044517 @default.
- W2097316923 cites W2081928466 @default.
- W2097316923 cites W2085626357 @default.
- W2097316923 cites W2089813733 @default.
- W2097316923 cites W2095496230 @default.
- W2097316923 cites W2107040028 @default.
- W2097316923 cites W2154941848 @default.
- W2097316923 doi "https://doi.org/10.1210/jcem.74.6.1592876" @default.
- W2097316923 hasPubMedId "https://pubmed.ncbi.nlm.nih.gov/1592876" @default.
- W2097316923 hasPublicationYear "1992" @default.
- W2097316923 type Work @default.
- W2097316923 sameAs 2097316923 @default.
- W2097316923 citedByCount "4" @default.
- W2097316923 crossrefType "journal-article" @default.
- W2097316923 hasAuthorship W2097316923A5014144073 @default.
- W2097316923 hasAuthorship W2097316923A5053601910 @default.
- W2097316923 hasAuthorship W2097316923A5090058184 @default.
- W2097316923 hasConcept C126322002 @default.
- W2097316923 hasConcept C134018914 @default.
- W2097316923 hasConcept C143228043 @default.
- W2097316923 hasConcept C16613235 @default.
- W2097316923 hasConcept C170493617 @default.
- W2097316923 hasConcept C187785154 @default.
- W2097316923 hasConcept C2776885963 @default.
- W2097316923 hasConcept C2777164284 @default.
- W2097316923 hasConcept C2777397205 @default.
- W2097316923 hasConcept C2777972943 @default.
- W2097316923 hasConcept C2778782382 @default.
- W2097316923 hasConcept C2778836221 @default.
- W2097316923 hasConcept C71315377 @default.
- W2097316923 hasConcept C71924100 @default.
- W2097316923 hasConcept C8264082 @default.
- W2097316923 hasConceptScore W2097316923C126322002 @default.
- W2097316923 hasConceptScore W2097316923C134018914 @default.
- W2097316923 hasConceptScore W2097316923C143228043 @default.
- W2097316923 hasConceptScore W2097316923C16613235 @default.
- W2097316923 hasConceptScore W2097316923C170493617 @default.
- W2097316923 hasConceptScore W2097316923C187785154 @default.
- W2097316923 hasConceptScore W2097316923C2776885963 @default.
- W2097316923 hasConceptScore W2097316923C2777164284 @default.
- W2097316923 hasConceptScore W2097316923C2777397205 @default.
- W2097316923 hasConceptScore W2097316923C2777972943 @default.
- W2097316923 hasConceptScore W2097316923C2778782382 @default.
- W2097316923 hasConceptScore W2097316923C2778836221 @default.
- W2097316923 hasConceptScore W2097316923C71315377 @default.
- W2097316923 hasConceptScore W2097316923C71924100 @default.
- W2097316923 hasConceptScore W2097316923C8264082 @default.
- W2097316923 hasLocation W20973169231 @default.
- W2097316923 hasLocation W20973169232 @default.
- W2097316923 hasOpenAccess W2097316923 @default.
- W2097316923 hasPrimaryLocation W20973169231 @default.
- W2097316923 hasRelatedWork W1963617861 @default.
- W2097316923 hasRelatedWork W2008493497 @default.
- W2097316923 hasRelatedWork W2017681441 @default.
- W2097316923 hasRelatedWork W2034402330 @default.
- W2097316923 hasRelatedWork W2062847990 @default.
- W2097316923 hasRelatedWork W2063489388 @default.
- W2097316923 hasRelatedWork W2075442956 @default.
- W2097316923 hasRelatedWork W2086583026 @default.
- W2097316923 hasRelatedWork W2107474202 @default.
- W2097316923 hasRelatedWork W2160022970 @default.
- W2097316923 isParatext "false" @default.
- W2097316923 isRetracted "false" @default.
- W2097316923 magId "2097316923" @default.
- W2097316923 workType "article" @default.