Development of a Radioimmunoassay for European Eel Growth Hormone and Application to the Study of Silvering and Experimental Fasting

Marchelidon, J.; Schmitz, Monika; Houdebine, L.M.; Vidal, B.; Belle, Nadine Le; Dufour, Sylvie

doi:10.1006/gcen.1996.0079

Cited by 42 publications

(37 citation statements)

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“…1) GH pituitary content was high in control eels (102 16 µg/pituitary), in agreement with previous studies (Marchelidon et al 1996). Chronic treatment with T 3 or T 4 significantly (P<0·05) reduced eel pituitary GH content by about 50% of control values (Fig.…”

Section: Resultssupporting

confidence: 92%

“…Accordingly, no significant differences in body weight were observed between control and T 3 -or T 4 -treated fish at the end of the experiment. However, in vivo inhibitory effects of THs on GH could still reflect indirect actions such as changes in GH response to fasting (Marchelidon et al 1996) or other indirect pathways.…”

Section: Discussionmentioning

confidence: 99%

“…GH levels from pituitary extracts, sera, cellular contents, and culture media were assayed using an homologous RIA for eel GH (Marchelidon et al 1996). Results from in vivo studies were expressed as µg/pituitary and ng/ml.…”

Section: Radioimmunoassaysmentioning

confidence: 99%

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Evidence for a negative feedback in the control of eel growth hormone by thyroid hormones

Rousseau¹,

Belle²,

Sbaihi³

et al. 2002

Journal of Endocrinology

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The regulation of growth hormone (GH) by thyroid hormones (THs) has been shown to present species variation. We investigated the regulation of GH in the eel, a representative of an ancient group of teleosts. In vivo administration of triiodothyronine (T 3 ) or thyroxine (T 4 ) significantly reduced pituitary and serum GH levels, as measured by homologous RIA. In order to investigate the ability of THs to regulate GH production directly at the pituitary level, we used a long-term, serum-free primary culture of eel pituitary cells. Both T 3 and T 4 inhibited GH release in a concentration-dependent manner, producing up to 50% inhibition at 10 nM, with an ED 50 of <0·2 nM, within the range of their physiological circulating levels. Other hormones also acting via the nuclear receptor superfamily, such as sex steroids (testosterone, estradiol and progesterone) and corticosteroid (cortisol), had no effect on GH release in vitro, underlining the specificity of the regulatory effect of THs on GH. Measurement of both GH release and cellular content for calculation of GH production in vitro indicated that THs not only inhibited GH release but also GH synthesis. Dot-blot assay of GH messenger RNA (mRNA) using an homologous eel cDNA probe showed a decrease in GH mRNA levels in cells cultured in the presence of T 3 , as compared with control cells. This demonstrated that the inhibition of T 3 on GH synthesis was mediated by a decrease in GH mRNA steady state levels. In conclusion, we demonstrate inhibitory regulation of eel GH synthesis and release by THs, exerted directly at the pituitary level. These data contrast with the rat, where THs are known to have a stimulatory effect and suggest that the pattern observed here in an early vertebrate and also found in birds, reptiles and some mammals including humans, may represent an ancestral and more generalized vertebrate pattern of TH regulation of pituitary GH.

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Section: Resultssupporting

confidence: 92%

Section: Discussionmentioning

confidence: 99%

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Evidence for a negative feedback in the control of eel growth hormone by thyroid hormones

Rousseau¹,

Belle²,

Sbaihi³

et al. 2002

Journal of Endocrinology

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“…A partir du broyat de chaque tête de civelle, les teneurs en hormones de croissance sont estimées individuellement suivant la méthodologie définie par MARCHELIDON et al, (1996).…”

Section: Figureunclassified

“…Bien qu'elle ne soit pas identifiée par FONTAINE et CALLAMAND (1941) comme jouant un rôle majeur dans la migration des civelles, l'hormone de croissance est impliquée dans plusieurs mécanismes susceptibles d'influer sur le comportement migratoire. En effet, outre son rôle dans la croissance, cette hormone hypophysaire favorise généralement un métabolisme élevé, en particulier dans les situations de détresse physiologique comme le stress ou le jeûne (MARCHELIDON et al, 1996 ;ROUSSEAU et al, 1999). Elle jouerait ainsi un rôle d"hormone de survie" chez les téléostéens (BJORNSSON, 1997 pour une revue).…”

Section: Introductionunclassified

VARIABILITES MORPHOLOGIQUE ET DU TAUX D’HORMONE DE CROISSANCE DES CIVELLES D'ANGUILLES EUROPEENNES (Anguilla anguilla) DANS L'ESTUAIRE DE LA GIRONDE AU COURS DE LA SAISON 1997-1998

Lambert

Sbaihi

Rochard

et al. 2003

Bull. Fr. Pêche Piscic.

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Mots clef : Anguilla anguilla, civelle, morphologie, hormone de croissance, migration MORPHOLOGICAL AND GROWTH HORMONE VARIABILITIES OF EUROPEAN GLASS-EEL (Anguilla anguilla) IN GIRONDE ESTUARY DURING 1997-1998 SEASON ABSTRACTThe aim of this study is to complete the morphological description of Gironde glass eels according to a physiological parameter, the growth hormone. The incoming flux had been observed during the migration season 1997-1998. 303 glass eels of pigmentation stage Vb were caught and individually analysed. The length and the weight of the glass eels decreased in February, the condition factor only in March. The growth hormone rate increased from an average of 6 ng/pituitary in December to an average of 16 ng/pituitary in February and March and up to an average around 20 ng/pituitary in April and May. The most credible hypothesis is that the first incoming glass eels show a smaller distress level than the last ones.

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The Eel

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Development of a Radioimmunoassay for European Eel Growth Hormone and Application to the Study of Silvering and Experimental Fasting

Cited by 42 publications

References 0 publications

Evidence for a negative feedback in the control of eel growth hormone by thyroid hormones

Evidence for a negative feedback in the control of eel growth hormone by thyroid hormones

VARIABILITES MORPHOLOGIQUE ET DU TAUX D’HORMONE DE CROISSANCE DES CIVELLES D'ANGUILLES EUROPEENNES (Anguilla anguilla) DANS L'ESTUAIRE DE LA GIRONDE AU COURS DE LA SAISON 1997-1998

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