Les hormones gonadotropes de l'hypophyse : biochimie et biologie comparées ; spécificité et évolution

Fontaine, Y.A.

doi:10.1051/rnd:19800302

Cited by 13 publications

(5 citation statements)

References 30 publications

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“…This is in agreement with previous biochemical and immunological data (Fontaine, 1980). Our preliminary results show that oestradiol treatment enhances the putative GTH-II ß-subunit mRNA level in the eel, as estimated by hybridization with the ODN probe and also with the specific cDNA probe.…”

Section: Discussionsupporting

confidence: 93%

Molecular cloning and sequence analysis of the cDNA for the putative β subunit of the type-II gonadotrophin from the European eel

Quérat

Moumni²,

Jutisz³

et al. 1990

Journal of Molecular Endocrinology

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Oestradiol treatment enhances type-II gonadotrophin (GTH-II) synthesis in the European eel (Anguilla anguilla) at the silver stage. As a first step in studying the molecular mechanisms involved in this stimulation, we cloned and characterized the cDNA encoding the beta subunit of eel GTH-II. A cDNA library was constituted in lambda gt10 from oestradiol-treated eels. It was screened using an oligodeoxyribonucleotide mixed probe designed to be complementary to a highly conserved region of cDNAs from several LH-related beta subunits. Several clones were obtained and four were subcloned in pUC13 and sequenced. The longest clones comprised a 420 bp coding sequence, plus 5' and 3' untranslated regions of 36 and 172 bp respectively. Comparison with GTH-II from other teleost fish permitted the localization of the putative cleavage site of a 24 amino acid signal peptide. The resulting 116 amino acid apopeptide had well-conserved cysteine positions and a putative N-linked glycosylation site; homology was 70-80% with GTH-II from other fish, 45% with LH from mammals and birds, 38% with mammalian FSH and only 35% with fish GTH-I. Preliminary results indicated a strong positive effect of oestradiol treatment on the level of the putative GTH-II beta-subunit mRNA. This supports our proposal that the European eel provides a suitable model for studying the positive regulation of gonadotrophin synthesis by gonadal steroids.

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Section: Discussionsupporting

confidence: 93%

Molecular cloning and sequence analysis of the cDNA for the putative β subunit of the type-II gonadotrophin from the European eel

Quérat

Moumni²,

Jutisz³

et al. 1990

Journal of Molecular Endocrinology

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“…Non-linearity of the Scatchard plot is generally attributed to heterogeneity of the receptor sites, with the presence of two 'orders' of affinity. Such an hypothesis, previously proposed by Fontaine (1980), would be particularly attractive in the male fish model, where GtH can stimulate androgen production and can control all the stages of spermatogenesis (see Billard et al 1982) while in mammals two hormones, FSH and LH regulate the activityof the two testicular compartments (respectively seminiferous tubules and interstitial tissue). Binding tests performed on fresh tissue, or on more purified membrane fractions also revealed two classes of binding sites (data not shown).…”

Section: Discussionmentioning

confidence: 99%

Gonadotropic hormone (GtH) receptors in the testis of the troutSalmo gairdneri: in vitro studies

Breton

Bougoussa

1988

Fish Physiol Biochem

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A particulate fraction obtained from trout testis at the time of spermiation shows saturable binding sites for(125)I-labeled salmon gonadotropin ((125)I-GtH). Non-gonadal tissues (liver, muscle and spleen) did not demonstrate specific(125)I-GtH binding. The tracer's specific activity was determined by the self-displacement method (18 to 30 μCi/μg). Maximal specific binding ability of(125)I-GtH varied from 20 to 30% of the labelled ligand added, depending on the hormone preparation. Specific binding of(125)I-GtH to 20 mg of the testis membrane varied from 40 to 85% of the total binding depending on the method of membrane prepratation, and was competitively inhibited by concentrations of unlabelled GtH ranging from ca 1 to 1000 ng/ml of incubate. Gonadotropin of mammalian origin, ovine TSH or salmon prolactin competed only weakly, or not at all, for testicular gonadotropin binding sites (relative potencies s-GtH>>FSH=hCG>s-PRL>bTSH). Scatchard analysis of equilibrium binding studies shows that saturable gonadotropin binding was due to a class of high affinity binding sites (sites I Ka≊3×10(10) M(-1)) and possibly to a second class of lower affinity binding sites (sites II Ka=5 to 14×10(8) M(-1)). The binding capacity of sites I, as measured in enriched membrane preparations, was 45±18 fmoles/g of testis during the period of spermiation. The concentration of GtH required to obtain half maximal displacement of(125)I-GtH in the binding studies was of the same order of magnitude as the apparent ED50 for GtH stimulation of 11-Cetotestosterone (11KT) secretion by trout testesin vitro. Mammalian LH and FSH were 100 to 1000 folds less potent than salmor GtH to increase 11 KT secretion.

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“…According to Fontaine and Burzawa-G6rard (1977), TSH and GTH are derived from a common molecule. This primitive hormone also comprising two subunits and/3 may have led to the differentiation of TSH and GTH, by modification of the/3 subunit carrying the functional specificity, while the ~ subunit is responsible for the species specificity (Fontaine and Burzawa-G6rard 1977;Fontaine 1980). Such a differentiation of TSH and GTH is well established in teleosts and is documented by several studies on the immunological relationships between glycoproteic hormones and their subunits (Billard et al 1971;Burzawa-G6rard and Fontaine 1972;Breton et al 1973;Burzawa-G6rard 1974;Schreibman and Margolis-Kazan 1979;Burzawa-G6rard et al 1976Burzawa-G6rard et al , 1980Olivereau and Nagahama 1983).…”

Section: Antiserum Against Umshmentioning

confidence: 99%

Immunohistochemical investigation of the pituitary of the sturgeon (Acipenser baeri, Chondrostei)

Pelissero

Nunez

Menn

et al. 1988

Fish Physiol Biochem

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An immunohistochemical study of the sturgeon (Acipenser baeri) pituitary was undertaken using antisera directed against hormones from various classes of vertebrates, including the only pituitary hormone available from sturgeon, gonadotrophin. A positive reaction was obtained after application of antisera towards the following hormones 1-24 synthetic ACTH (1-24 ACTH), melanophore stimulating hormone (MSH), ovine prolactin (oPRL), ovine growth hormone (oGH), salmon growth hormone (sGH), carp gonadotrophin (cGTH) and its beta subunit (βcGTH), sturgeon gonadotrophin (aciGTH), carp thyrotrophin (cTSH) and β subunit of the human thyrotrophin (βhTSH). The results demonstrate that, in general, the sturgeon pituitary resembles that of teleosts as regards the distribution of the different cell types: ACTH and PRL cells in the rostral pars distalis, GTH, TSH and GH cells in the proximal pars distalis and MSH and PAS-cells in pars intermedia. In addition to the topographical organization of the sturgeon pituitary, this study provides data on the immunological relationships between sturgeon pituitary hormones and those of other vertebrates.

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Les hormones gonadotropes de l'hypophyse : biochimie et biologie comparées ; spécificité et évolution

Cited by 13 publications

References 30 publications

Molecular cloning and sequence analysis of the cDNA for the putative β subunit of the type-II gonadotrophin from the European eel

Molecular cloning and sequence analysis of the cDNA for the putative β subunit of the type-II gonadotrophin from the European eel

Gonadotropic hormone (GtH) receptors in the testis of the troutSalmo gairdneri: in vitro studies

Immunohistochemical investigation of the pituitary of the sturgeon (Acipenser baeri, Chondrostei)

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