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Registro Completo |
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Biblioteca(s): |
Embrapa Caprinos e Ovinos. |
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Data corrente: |
01/02/2000 |
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Data da última atualização: |
10/08/2023 |
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Autoria: |
NIKOLARAKIS, K. E.; PFEIFFER, D. G.; ALMEIDA, O. F. X.; HERZ, A. |
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Título: |
Opioid modulation of LHRH release in vitro depends upon levels of testosterone in vivo. |
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Ano de publicação: |
1986 |
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Fonte/Imprenta: |
Neuroendocrinology, v. 44, n. 3, p. 314-319, 1986. |
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DOI: |
10.1159/000124662. |
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Idioma: |
Inglês |
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Conteúdo: |
Abstract: The in vitro release of LHRH from hypothalami of adult male rats (intact, 5-day castrates, 5-day castrates replaced with various doses of testosterone) was measured under basal conditions and after the addition of KCl, the opiate antagonist naloxone or the opiate agonist DAGO to the perifusion medium. Hypothalami from all treatment groups responded to 56 mM KCl with an increased output of LHRH. LHRH release was also induced by naloxone (10(-6)M), but only from tissues derived from intacts and castrates given physiological doses of testosterone. The opiate agonist DAGO (10(-6)M) did not alter the basal release of LHRH; it, however, caused a significant decrease in the K+-induced release of LHRH from hypothalami derived from intact rats and rats replaced with physiological levels of testosterone but not from those derived from castrate rats or castrate rats replaced with small amounts of testosterone. The specificity of this latter response was shown by its reversibility with naloxone. The lack of DAGO effects upon tissues from rats with low levels of steroid implied steroid dependency of the response to opioidergic influences and indeed, the response to DAGO was restored when testosterone was replaced at physiological doses. Measurement of hypothalamic LHRH content showed no significant differences between tissues obtained from intact, castrate and testosterone-replaced castrate rats. These in vitro data support the view that the inhibitory influence of opioids upon LHRH release depends on the presence of gonadal steroids in vivo. MenosAbstract: The in vitro release of LHRH from hypothalami of adult male rats (intact, 5-day castrates, 5-day castrates replaced with various doses of testosterone) was measured under basal conditions and after the addition of KCl, the opiate antagonist naloxone or the opiate agonist DAGO to the perifusion medium. Hypothalami from all treatment groups responded to 56 mM KCl with an increased output of LHRH. LHRH release was also induced by naloxone (10(-6)M), but only from tissues derived from intacts and castrates given physiological doses of testosterone. The opiate agonist DAGO (10(-6)M) did not alter the basal release of LHRH; it, however, caused a significant decrease in the K+-induced release of LHRH from hypothalami derived from intact rats and rats replaced with physiological levels of testosterone but not from those derived from castrate rats or castrate rats replaced with small amounts of testosterone. The specificity of this latter response was shown by its reversibility with naloxone. The lack of DAGO effects upon tissues from rats with low levels of steroid implied steroid dependency of the response to opioidergic influences and indeed, the response to DAGO was restored when testosterone was replaced at physiological doses. Measurement of hypothalamic LHRH content showed no significant differences between tissues obtained from intact, castrate and testosterone-replaced castrate rats. These in vitro data support the view that the inhibitory influence of opioids upon... Mostrar Tudo |
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Palavras-Chave: |
Enkephalins; LHRH; Opioide; Orchiectomy; Sex steroids. |
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Thesagro: |
Rato; Testosterona. |
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Thesaurus Nal: |
Endorphins; Gonadotropin-releasing hormone; Hypothalamus; Luteinizing hormone; Metabolism; Pharmacology; Physiology; Rats; Synaptic transmission; Testosterone. |
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Categoria do assunto: |
L Ciência Animal e Produtos de Origem Animal |
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Marc: |
LEADER 02575naa a2200373 a 4500
001 1524096
005 2023-08-10
008 1986 bl uuuu u00u1 u #d
024 7 $a10.1159/000124662.$2DOI
100 1 $aNIKOLARAKIS, K. E.
245 $aOpioid modulation of LHRH release in vitro depends upon levels of testosterone in vivo.$h[electronic resource]
260 $c1986
520 $aAbstract: The in vitro release of LHRH from hypothalami of adult male rats (intact, 5-day castrates, 5-day castrates replaced with various doses of testosterone) was measured under basal conditions and after the addition of KCl, the opiate antagonist naloxone or the opiate agonist DAGO to the perifusion medium. Hypothalami from all treatment groups responded to 56 mM KCl with an increased output of LHRH. LHRH release was also induced by naloxone (10(-6)M), but only from tissues derived from intacts and castrates given physiological doses of testosterone. The opiate agonist DAGO (10(-6)M) did not alter the basal release of LHRH; it, however, caused a significant decrease in the K+-induced release of LHRH from hypothalami derived from intact rats and rats replaced with physiological levels of testosterone but not from those derived from castrate rats or castrate rats replaced with small amounts of testosterone. The specificity of this latter response was shown by its reversibility with naloxone. The lack of DAGO effects upon tissues from rats with low levels of steroid implied steroid dependency of the response to opioidergic influences and indeed, the response to DAGO was restored when testosterone was replaced at physiological doses. Measurement of hypothalamic LHRH content showed no significant differences between tissues obtained from intact, castrate and testosterone-replaced castrate rats. These in vitro data support the view that the inhibitory influence of opioids upon LHRH release depends on the presence of gonadal steroids in vivo.
650 $aEndorphins
650 $aGonadotropin-releasing hormone
650 $aHypothalamus
650 $aLuteinizing hormone
650 $aMetabolism
650 $aPharmacology
650 $aPhysiology
650 $aRats
650 $aSynaptic transmission
650 $aTestosterone
650 $aRato
650 $aTestosterona
653 $aEnkephalins
653 $aLHRH
653 $aOpioide
653 $aOrchiectomy
653 $aSex steroids
700 1 $aPFEIFFER, D. G.
700 1 $aALMEIDA, O. F. X.
700 1 $aHERZ, A.
773 $tNeuroendocrinology$gv. 44, n. 3, p. 314-319, 1986.
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Registro original: |
Embrapa Caprinos e Ovinos (CNPC) |
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