Ontogenesis of [3H]serotonin binding sites in the hypothalamus of the female rat: Relation to serotonin-induced LH release in moxestrol-pretreated rats
The release of luteinizing hormone (LH) evoked by exogenous serotonin (5 mg/kg, i.p.) was measured at different developmental ages in the female rat. Since LH response to serotonin is modulated by estrogen, moxestrol, a synthetic compound which does not bind to α-fetoprotein, was administered 48 h b...
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1986
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| Acceso en línea: | https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_01653806_v25_n1_p111_BecuVillalobos http://hdl.handle.net/20.500.12110/paper_01653806_v25_n1_p111_BecuVillalobos |
| Aporte de: |
| Sumario: | The release of luteinizing hormone (LH) evoked by exogenous serotonin (5 mg/kg, i.p.) was measured at different developmental ages in the female rat. Since LH response to serotonin is modulated by estrogen, moxestrol, a synthetic compound which does not bind to α-fetoprotein, was administered 48 h before serotonin or saline injections. Serotonin was ineffective in releasing LH in 5-day females pretreated with moxestrol; the response increased abruptly at 12 and 18 days and from then onwards decreased gradually. This is in clear contrast to the development of the serotonin-induced prolactin release, which is absent in the first postnatal week, becomes evident on day 12 and increases gradually as the rat approaches puberty. In a second group of experiments, the ontogenesis of hypothalamic-preoptic suprachiasmatic [3H]serotonin binding was studied in 5-, 16-, 27- and 37-day-old female rats. A specific serotonergic binding site could be quantified at 5 days (Bmax 4.31 : 1.89 fmol/μg DNA; Kd:2.74 : 1.17 nM). A gradual increase of both, Bmax and Kd was observed as the animal matured: the number of binding sites almost doubled from day 16 to day 27, and increased even further by 37 days (Bmax 24.21 : 5.16 fmol/μg DNA). These data indicate: (a) a specific [3H]serotonin binding site in hypothalamic-preoptic suprachiasmatic area is present in the first postnatal week of the female rat: (b) Bmax and Kd values increase from 5 to 37 days of age; (c) serotonin-induced LH release in moxestrol-pretreated females is maximal in postnatal weeks 2-3; and (d) ontogenesis of serotonin binding sites in the hypothalamus is in correlation to prolactin, but not to LH release evoked by exogenously administered indoleamine. © 1986. |
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