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Joan Cerda - One of the best experts on this subject based on the ideXlab platform.

  • plasma levels of follicle stimulating and luteinizing hormones during the reproductive cycle of wild and cultured senegalese sole solea senegalensis
    Comparative Biochemistry and Physiology A-molecular & Integrative Physiology, 2016
    Co-Authors: Francois Chauvigne, Ana M Gomez, Elvira Fatsini, Neil Duncan, Judith Olle, Silvia Zanuy, Joan Cerda
    Abstract:

    The intensive culture of the Senegalese sole (Solea senegalensis) is hampered by the low or null fertilization rates exhibited by the first generation (F1) of reared males. To investigate the regulation of the reproductive processes in this species by the Pituitary Gonadotropins follicle-stimulating and luteinizing hormones (Fsh and Lh, respectively), we developed a highly sensitive and specific enzyme-linked immunosorbent assay (ELISA) for Lh measurements. Quantification of the Fsh and Lh plasma levels in cultured sole using the Lh ELISA developed here, and a previously developed ELISA for Fsh, indicated that in both males and females circulating Fsh steadily increased during autumn and winter and prior to the major spawning in spring, whereas an Lh surge occurred specifically during spawning. The increase in Fsh was associated with a rise of plasma levels of the steroid hormones testosterone (T), 11-ketotestosterone (11-KT) and estradiol-17β (E2), but that of Lh was concomitant with a strong decline of the levels of E2 in females and of 11-KT in males, possibly reflecting a rapid steroidogenic shift promoting the final maturation of gametes. Comparison of the plasma levels of Gonadotropins and steroids between wild and F1 fish during autumn and spring revealed that F1 males showed significantly lower plasma Lh titres compared to wild males, whereas the levels of T and 11-KT were similar or more elevated in the F1 fish. These data suggest that an impaired Lh secretion during spawning, and perhaps altered Lh-mediated mechanisms in the testis, may be underlying causes for the low reproductive performance of Senegalese sole F1 males.

  • functional and evolutionary analysis of flatfish gonadotropin receptors reveals cladal and lineage level divergence of the teleost glycoprotein receptor family
    Biology of Reproduction, 2010
    Co-Authors: Francois Chauvigne, Angele Tingaudsequeira, Maria Josep Agulleiro, Magdalena Calusinska, Ana M Gomez, Roderick Nigel Finn, Joan Cerda
    Abstract:

    Pituitary Gonadotropins, follicle-stimulating hormone (FSH), and luteinizing hormone (LH) act via their cognate glycoprotein hormone receptors (GpHRs), FSH receptor (FSHR), and LH/choriogonadotropin receptor (LHCGR) to regulate gonad physiology. Here, we show that the flatfish Senegalese sole (Solea senegalensis) expresses functional isoforms of fshr and lhcgr, but the genomic origin, ligand activation, and tissue distribution of the receptor transcripts are more complex than expected. By integrating the molecular phylogeny of GpHRs with the syntenic loci of vertebrate orthologs, and by subsequently characterizing the physical maps with the phylogeny of flanking genes, we found that vertebrate GpHRs have undergone a divergent evolution. In Teleostei, fshr genes have a common descent and can be classified as fshra, whereas lhcgrb genes exist as alternatively coded genes even in closely related species. Structural analyses of the receptors revealed that Fshra has an elongated ligand-binding domain, containi...

  • functional and evolutionary analysis of flatfish gonadotropin receptors reveals cladal and lineage level divergence of the teleost glycoprotein receptor family
    Biology of Reproduction, 2010
    Co-Authors: Francois Chauvigne, Angele Tingaudsequeira, Maria Josep Agulleiro, Magdalena Calusinska, Ana M Gomez, Roderick Nigel Finn, Joan Cerda
    Abstract:

    Pituitary Gonadotropins, follicle-stimulating hormone (FSH), and luteinizing hormone (LH) act via their cognate glycoprotein hormone receptors (GpHRs), FSH receptor (FSHR), and LH/choriogonadotropin receptor (LHCGR) to regulate gonad physiology. Here, we show that the flatfish Senegalese sole (Solea senegalensis) expresses functional isoforms of fshr and lhcgr, but the genomic origin, ligand activation, and tissue distribution of the receptor transcripts are more complex than expected. By integrating the molecular phylogeny of GpHRs with the syntenic loci of vertebrate orthologs, and by subsequently characterizing the physical maps with the phylogeny of flanking genes, we found that vertebrate GpHRs have undergone a divergent evolution. In Teleostei, fshr genes have a common descent and can be classified as fshra, whereas lhcgrb genes exist as alternatively coded genes even in closely related species. Structural analyses of the receptors revealed that Fshra has an elongated ligand-binding domain, containing an extra leucine-rich repeat that specifically arose in the Acanthomorpha because of exon duplication. Ectopic expression in Xenopus laevis oocytes demonstrated that sole Fshra responded to piscine Fsh and Lh, whereas Lhcgrba was preferentially activated by its cognate hormone. The expression pattern of sole fshra and lhcgrba in gonads during the reproductive cycle was consistent with earlier observations wherein Fshra regulates ovarian growth and spermatogenesis and Lhcgrb triggers gamete maturation, respectively. However, contrary to observations in other teleosts, fshra was localized exclusively in Sertoli cells of the testis, whereas lhcgrba was expressed in Leydig cells as well as in spermatids. These results demonstrate the presence of alternatively coded lhcgr isoforms (lhcgrba and lhcgrbb) in teleosts and suggest a role of the lhcgrba receptor in the differentiation of spermatids into spermatozoa in Senegalese sole.

  • molecular cloning of senegalese sole solea senegalensis follicle stimulating hormone and luteinizing hormone subunits and expression pattern during spermatogenesis
    General and Comparative Endocrinology, 2008
    Co-Authors: Joan Cerda, Francois Chauvigne, Maria J Agulleiro, Elena Marin, Silke Halm, Gonzalo Martinezrodriguez, Francisco Prat
    Abstract:

    Abstract Pituitary Gonadotropins (GTHs), follicle-stimulating hormone (FSH) and luteinizing hormone (LH), are key regulators of vertebrate reproduction. However, in teleosts with testis of semi-cystic type and asynchronous spermatogenesis, as the flatfish Senegalese sole ( Solea senegalensis ), the physiological roles of FSH and LH are still not well understood. To gain insight into this mechanism, full-length complementary DNAs (cDNAs) encoding Senegalese sole FSHβ and LHβ subunits, and the common glycoprotein α subunit (CGα), were cloned and sequenced. The three cDNAs consisted of 550, 582 and 744 nucleotides encoding peptides of 120, 148 and 132 amino acids, respectively. Comparison of the deduced amino acid sequences of sole FSHβ, LHβ and CGα with those from other teleosts indicated that cysteine residues and potential N-linked glycosylation sites were fully conserved with respect to other percomorphs and salmonids. However, the primary structure of FSHβ and LHβ in pleuronectiforms appeared to be highly divergent. In situ hybridization of mature male pituitaries showed that fshb , lhb and cga mRNAs were localized in the proximal pars distalis and in the periphery of pars intermedia . Real-time quantitative reverse transcription-polymerase chain reaction indicated that the levels of all three transcripts in the Pituitary of males increased during winter and spring, at the time when plasma levels of androgens raised and testicular germ cell development and spermatozoa production were stimulated. These results suggest that FSH and LH may regulate spermatogenesis in Senegalese sole similarly to that described for other teleosts with testis of cystic type and synchronous germ cell development.

Francois Chauvigne - One of the best experts on this subject based on the ideXlab platform.

  • plasma levels of follicle stimulating and luteinizing hormones during the reproductive cycle of wild and cultured senegalese sole solea senegalensis
    Comparative Biochemistry and Physiology A-molecular & Integrative Physiology, 2016
    Co-Authors: Francois Chauvigne, Ana M Gomez, Elvira Fatsini, Neil Duncan, Judith Olle, Silvia Zanuy, Joan Cerda
    Abstract:

    The intensive culture of the Senegalese sole (Solea senegalensis) is hampered by the low or null fertilization rates exhibited by the first generation (F1) of reared males. To investigate the regulation of the reproductive processes in this species by the Pituitary Gonadotropins follicle-stimulating and luteinizing hormones (Fsh and Lh, respectively), we developed a highly sensitive and specific enzyme-linked immunosorbent assay (ELISA) for Lh measurements. Quantification of the Fsh and Lh plasma levels in cultured sole using the Lh ELISA developed here, and a previously developed ELISA for Fsh, indicated that in both males and females circulating Fsh steadily increased during autumn and winter and prior to the major spawning in spring, whereas an Lh surge occurred specifically during spawning. The increase in Fsh was associated with a rise of plasma levels of the steroid hormones testosterone (T), 11-ketotestosterone (11-KT) and estradiol-17β (E2), but that of Lh was concomitant with a strong decline of the levels of E2 in females and of 11-KT in males, possibly reflecting a rapid steroidogenic shift promoting the final maturation of gametes. Comparison of the plasma levels of Gonadotropins and steroids between wild and F1 fish during autumn and spring revealed that F1 males showed significantly lower plasma Lh titres compared to wild males, whereas the levels of T and 11-KT were similar or more elevated in the F1 fish. These data suggest that an impaired Lh secretion during spawning, and perhaps altered Lh-mediated mechanisms in the testis, may be underlying causes for the low reproductive performance of Senegalese sole F1 males.

  • functional and evolutionary analysis of flatfish gonadotropin receptors reveals cladal and lineage level divergence of the teleost glycoprotein receptor family
    Biology of Reproduction, 2010
    Co-Authors: Francois Chauvigne, Angele Tingaudsequeira, Maria Josep Agulleiro, Magdalena Calusinska, Ana M Gomez, Roderick Nigel Finn, Joan Cerda
    Abstract:

    Pituitary Gonadotropins, follicle-stimulating hormone (FSH), and luteinizing hormone (LH) act via their cognate glycoprotein hormone receptors (GpHRs), FSH receptor (FSHR), and LH/choriogonadotropin receptor (LHCGR) to regulate gonad physiology. Here, we show that the flatfish Senegalese sole (Solea senegalensis) expresses functional isoforms of fshr and lhcgr, but the genomic origin, ligand activation, and tissue distribution of the receptor transcripts are more complex than expected. By integrating the molecular phylogeny of GpHRs with the syntenic loci of vertebrate orthologs, and by subsequently characterizing the physical maps with the phylogeny of flanking genes, we found that vertebrate GpHRs have undergone a divergent evolution. In Teleostei, fshr genes have a common descent and can be classified as fshra, whereas lhcgrb genes exist as alternatively coded genes even in closely related species. Structural analyses of the receptors revealed that Fshra has an elongated ligand-binding domain, containi...

  • functional and evolutionary analysis of flatfish gonadotropin receptors reveals cladal and lineage level divergence of the teleost glycoprotein receptor family
    Biology of Reproduction, 2010
    Co-Authors: Francois Chauvigne, Angele Tingaudsequeira, Maria Josep Agulleiro, Magdalena Calusinska, Ana M Gomez, Roderick Nigel Finn, Joan Cerda
    Abstract:

    Pituitary Gonadotropins, follicle-stimulating hormone (FSH), and luteinizing hormone (LH) act via their cognate glycoprotein hormone receptors (GpHRs), FSH receptor (FSHR), and LH/choriogonadotropin receptor (LHCGR) to regulate gonad physiology. Here, we show that the flatfish Senegalese sole (Solea senegalensis) expresses functional isoforms of fshr and lhcgr, but the genomic origin, ligand activation, and tissue distribution of the receptor transcripts are more complex than expected. By integrating the molecular phylogeny of GpHRs with the syntenic loci of vertebrate orthologs, and by subsequently characterizing the physical maps with the phylogeny of flanking genes, we found that vertebrate GpHRs have undergone a divergent evolution. In Teleostei, fshr genes have a common descent and can be classified as fshra, whereas lhcgrb genes exist as alternatively coded genes even in closely related species. Structural analyses of the receptors revealed that Fshra has an elongated ligand-binding domain, containing an extra leucine-rich repeat that specifically arose in the Acanthomorpha because of exon duplication. Ectopic expression in Xenopus laevis oocytes demonstrated that sole Fshra responded to piscine Fsh and Lh, whereas Lhcgrba was preferentially activated by its cognate hormone. The expression pattern of sole fshra and lhcgrba in gonads during the reproductive cycle was consistent with earlier observations wherein Fshra regulates ovarian growth and spermatogenesis and Lhcgrb triggers gamete maturation, respectively. However, contrary to observations in other teleosts, fshra was localized exclusively in Sertoli cells of the testis, whereas lhcgrba was expressed in Leydig cells as well as in spermatids. These results demonstrate the presence of alternatively coded lhcgr isoforms (lhcgrba and lhcgrbb) in teleosts and suggest a role of the lhcgrba receptor in the differentiation of spermatids into spermatozoa in Senegalese sole.

  • molecular cloning of senegalese sole solea senegalensis follicle stimulating hormone and luteinizing hormone subunits and expression pattern during spermatogenesis
    General and Comparative Endocrinology, 2008
    Co-Authors: Joan Cerda, Francois Chauvigne, Maria J Agulleiro, Elena Marin, Silke Halm, Gonzalo Martinezrodriguez, Francisco Prat
    Abstract:

    Abstract Pituitary Gonadotropins (GTHs), follicle-stimulating hormone (FSH) and luteinizing hormone (LH), are key regulators of vertebrate reproduction. However, in teleosts with testis of semi-cystic type and asynchronous spermatogenesis, as the flatfish Senegalese sole ( Solea senegalensis ), the physiological roles of FSH and LH are still not well understood. To gain insight into this mechanism, full-length complementary DNAs (cDNAs) encoding Senegalese sole FSHβ and LHβ subunits, and the common glycoprotein α subunit (CGα), were cloned and sequenced. The three cDNAs consisted of 550, 582 and 744 nucleotides encoding peptides of 120, 148 and 132 amino acids, respectively. Comparison of the deduced amino acid sequences of sole FSHβ, LHβ and CGα with those from other teleosts indicated that cysteine residues and potential N-linked glycosylation sites were fully conserved with respect to other percomorphs and salmonids. However, the primary structure of FSHβ and LHβ in pleuronectiforms appeared to be highly divergent. In situ hybridization of mature male pituitaries showed that fshb , lhb and cga mRNAs were localized in the proximal pars distalis and in the periphery of pars intermedia . Real-time quantitative reverse transcription-polymerase chain reaction indicated that the levels of all three transcripts in the Pituitary of males increased during winter and spring, at the time when plasma levels of androgens raised and testicular germ cell development and spermatozoa production were stimulated. These results suggest that FSH and LH may regulate spermatogenesis in Senegalese sole similarly to that described for other teleosts with testis of cystic type and synchronous germ cell development.

K L Parker - One of the best experts on this subject based on the ideXlab platform.

  • 0888-8809/02/$15.00/0 Molecular Endocrinology 16(10):2360–2370 Printed in U.S.A. Copyright © 2002 by The Endocrine Society doi: 10.1210/me.2002-0003 Development of a Transgenic Green Fluorescent Protein Lineage Marker for Steroidogenic Factor 1
    2013
    Co-Authors: Nancy R Stallings, Marit Bakke, Gregor Majdic, Neil A Hanley, Liping Zhao, K L Parker
    Abstract:

    Knockout mice lacking steroidogenic factor 1 (SF-1, officially designated Nr5a1) have a complex phenotype that includes adrenal and gonadal agenesis, impaired expression of Pituitary Gonadotropins, and structural abnormalities of the ventromedial hypothalamic nucleus. To explore further how SF-1 regulates endocrine function, we used bacterial artificial chromosome transgenesis to develop a lineage marker for SF-1-expressing cells. A genomic fragment containing 50 kb of the mouse Nr5a1 gene was used to target enhanced green fluorescent protein (eGFP) in transgenic mice. These sequences directed eGFP to multiple cell lineages that express SF-1, including steroidogenic cells of the adrenal cortex, testes, and ovaries, neurons of the ventromedial hypothalamic nucleus, and reticuloendothelial cells of the spleen. Despite the proven role of SF-1 in gonadotrope function, eGFP was not expressed in the anterior Pituitary. These experiments show that 50 kb of the mouse Nr5a1 gene can target transgenic expression to multiple cell lineages that normally express SF-1. The SF-1/eGFP transgenic mice will facilitate approaches such as fluorescence-activated cell sorting of eGFP-positive cells and DNA microarray analyses to expand our understanding of the multiple actions of SF-1 in endocrine development an

  • cell specific knockout of steroidogenic factor 1 reveals its essential roles in gonadal function
    Molecular Endocrinology, 2004
    Co-Authors: Pancharatnam Jeyasuria, Soazik P Jamin, Axel P N Themmen, Richard R Behringer, Yayoi Ikeda, Dirk G. De Rooij, K L Parker
    Abstract:

    Knockout (KO) mice lacking the orphan nuclear receptor steroidogenic factor 1 (SF-1, officially designated Nr5a1) have a compound endocrine phenotype that includes adrenal and gonadal agenesis, impaired expression of Pituitary Gonadotropins, and structural abnormalities of the ventromedial hypothalamic nucleus. To inactivate a conditional SF-1 allele in the gonads, we targeted the expression of Cre recombinase with a knock-in allele of the anti-Mullerian hormone type 2 receptor locus. In testes, Cre was expressed in Leydig cells. The testes of adult gonad-specific SF-1 KO mice remained at the level of the bladder and were markedly hypoplastic, due at least partly to impaired spermatogenesis. Histological abnormalities of the testes were seen from early developmental stages and were associated with markedly decreased Leydig cell expression of two essential components of testosterone biosynthesis, Cyp11a and the steroidogenic acute regulatory protein. In females, the anti-Mullerian hormone type 2 receptor-C...

  • development of a transgenic green fluorescent protein lineage marker for steroidogenic factor 1
    Molecular Endocrinology, 2002
    Co-Authors: Nancy R Stallings, Marit Bakke, Gregor Majdic, Neil A Hanley, K L Parker
    Abstract:

    Knockout mice lacking steroidogenic factor 1 (SF-1, officially designated Nr5a1) have a complex phenotype that includes adrenal and gonadal agenesis, impaired expression of Pituitary Gonadotropins, and structural abnormalities of the ventromedial hypothalamic nucleus. To explore further how SF-1 regulates endocrine function, we used bacterial artificial chromosome transgenesis to develop a lineage marker for SF-1-expressing cells. A genomic fragment containing 50 kb of the mouse Nr5a1 gene was used to target enhanced green fluorescent protein (eGFP) in transgenic mice. These sequences directed eGFP to multiple cell lineages that express SF-1, including steroidogenic cells of the adrenal cortex, testes, and ovaries, neurons of the ventromedial hypothalamic nucleus, and reticuloendothelial cells of the spleen. Despite the proven role of SF-1 in gonadotrope function, eGFP was not expressed in the anterior Pituitary. These experiments show that 50 kb of the mouse Nr5a1 gene can target transgenic expression to...

  • steroidogenic factor 1 sf1 is essential for Pituitary gonadotrope function
    Development, 2001
    Co-Authors: Marit Bakke, Yelena Krimkevich, Albert F Parlow, Lisa J Cushman, K L Parker
    Abstract:

    Knockout mice lacking the orphan nuclear receptor steroidogenic factor 1 (SF1) exhibit a complex endocrine phenotype that includes adrenal and gonadal agenesis, impaired expression of Pituitary Gonadotropins, and absence of the ventromedial hypothalamic nucleus (VMH). These multiple defects complicate efforts to delineate primary versus secondary effects of SF1 deficiency in different tissues, such that its direct role in gonadotropes remains uncertain. To define this role, we have expressed Cre recombinase driven by the promoter region of the common alpha subunit of glycoprotein hormones (alpha GSU), thereby inactivating a loxP-modified SF1 locus in the anterior Pituitary gland. Although Pituitary-specific SF1 knockout mice were fully viable, they were sterile and failed to develop normal secondary sexual characteristics. Their adrenal glands and VMH appeared normal histologically, but their testes and ovaries were severely hypoplastic. alpha GSU-Cre, loxP mice had normal levels of most Pituitary hormones, but had markedly decreased expression of LH and FSH. Treatment with exogenous Gonadotropins stimulated gonadal steroidogenesis, inducing germ cell maturation in males and follicular and uterine maturation in females--establishing that the gonads can respond to Gonadotropins. The Pituitary-specific SF1 knockout mice are a novel genetic model of hypogonadotropic hypogonadism that establishes essential role(s) of SF1 in Pituitary gonadotropes.

Magdalena Calusinska - One of the best experts on this subject based on the ideXlab platform.

  • functional and evolutionary analysis of flatfish gonadotropin receptors reveals cladal and lineage level divergence of the teleost glycoprotein receptor family
    Biology of Reproduction, 2010
    Co-Authors: Francois Chauvigne, Angele Tingaudsequeira, Maria Josep Agulleiro, Magdalena Calusinska, Ana M Gomez, Roderick Nigel Finn, Joan Cerda
    Abstract:

    Pituitary Gonadotropins, follicle-stimulating hormone (FSH), and luteinizing hormone (LH) act via their cognate glycoprotein hormone receptors (GpHRs), FSH receptor (FSHR), and LH/choriogonadotropin receptor (LHCGR) to regulate gonad physiology. Here, we show that the flatfish Senegalese sole (Solea senegalensis) expresses functional isoforms of fshr and lhcgr, but the genomic origin, ligand activation, and tissue distribution of the receptor transcripts are more complex than expected. By integrating the molecular phylogeny of GpHRs with the syntenic loci of vertebrate orthologs, and by subsequently characterizing the physical maps with the phylogeny of flanking genes, we found that vertebrate GpHRs have undergone a divergent evolution. In Teleostei, fshr genes have a common descent and can be classified as fshra, whereas lhcgrb genes exist as alternatively coded genes even in closely related species. Structural analyses of the receptors revealed that Fshra has an elongated ligand-binding domain, containi...

  • functional and evolutionary analysis of flatfish gonadotropin receptors reveals cladal and lineage level divergence of the teleost glycoprotein receptor family
    Biology of Reproduction, 2010
    Co-Authors: Francois Chauvigne, Angele Tingaudsequeira, Maria Josep Agulleiro, Magdalena Calusinska, Ana M Gomez, Roderick Nigel Finn, Joan Cerda
    Abstract:

    Pituitary Gonadotropins, follicle-stimulating hormone (FSH), and luteinizing hormone (LH) act via their cognate glycoprotein hormone receptors (GpHRs), FSH receptor (FSHR), and LH/choriogonadotropin receptor (LHCGR) to regulate gonad physiology. Here, we show that the flatfish Senegalese sole (Solea senegalensis) expresses functional isoforms of fshr and lhcgr, but the genomic origin, ligand activation, and tissue distribution of the receptor transcripts are more complex than expected. By integrating the molecular phylogeny of GpHRs with the syntenic loci of vertebrate orthologs, and by subsequently characterizing the physical maps with the phylogeny of flanking genes, we found that vertebrate GpHRs have undergone a divergent evolution. In Teleostei, fshr genes have a common descent and can be classified as fshra, whereas lhcgrb genes exist as alternatively coded genes even in closely related species. Structural analyses of the receptors revealed that Fshra has an elongated ligand-binding domain, containing an extra leucine-rich repeat that specifically arose in the Acanthomorpha because of exon duplication. Ectopic expression in Xenopus laevis oocytes demonstrated that sole Fshra responded to piscine Fsh and Lh, whereas Lhcgrba was preferentially activated by its cognate hormone. The expression pattern of sole fshra and lhcgrba in gonads during the reproductive cycle was consistent with earlier observations wherein Fshra regulates ovarian growth and spermatogenesis and Lhcgrb triggers gamete maturation, respectively. However, contrary to observations in other teleosts, fshra was localized exclusively in Sertoli cells of the testis, whereas lhcgrba was expressed in Leydig cells as well as in spermatids. These results demonstrate the presence of alternatively coded lhcgr isoforms (lhcgrba and lhcgrbb) in teleosts and suggest a role of the lhcgrba receptor in the differentiation of spermatids into spermatozoa in Senegalese sole.

Michiya Matsuyama - One of the best experts on this subject based on the ideXlab platform.

  • molecular characterization and functional analysis of Pituitary gnrh receptor in a commercial scombroid fish chub mackerel scomber japonicus
    General and Comparative Endocrinology, 2017
    Co-Authors: Sanny David Pacheco Lumayno, Hirofumi Ohga, Sethu Selvaraj, Mitsuo Nyuji, Akihiko Yamaguchi, Michiya Matsuyama
    Abstract:

    The gonadotropin-releasing hormone (GnRH) is essential during pubertal onset, for its regulation of the synthesis and release of Pituitary Gonadotropins. Its action is mediated by GnRH receptors (GnRHRs) in the Pituitary gonadotrophs. Our previous study demonstrated that the chub mackerel brain expresses three GnRH forms (gnrh1, gnrh2, and gnrh3), and that only GnRH1 neurons innervate anterior Pituitary regions. Furthermore, chub mackerel gnrh1 mRNA exhibited a significant increase at pubertal onset. The present study aimed to isolate the functional GnRHR form involved in chub mackerel puberty. The open reading frame of our cloned receptor encodes 428 amino acids and contains seven transmembrane domains. Phylogenetic analysis also indicated clustering with other teleost-type IIB GnRHRs, mainly those involved in reproduction. Reporter gene assay results showed that all four synthetic peptides (GnRH1, GnRH2, GnRH3, and GnRH analogue) bind to the cloned receptor. Three deduced GnRH ligands stimulated luteinizing hormone (LH) release from cultured Pituitary cells in vitro. Receptor gene expression was mainly detected in the Pituitary and showed an increasing trend in the developing gonadal stages of both sexes during the pubertal process; this process was synchronous with previous studies of follicle-stimulating hormone beta (fshβ) and lhβ gene expression in chub mackerel. These results suggest that the cloned receptor is likely involved in the regulation of pubertal onset in this species. Therefore, we have designated the receptor cmGnRHR1.

  • characterization localization and stage dependent gene expression of gonadotropin receptors in chub mackerel scomber japonicus ovarian follicles
    Biology of Reproduction, 2013
    Co-Authors: Mitsuo Nyuji, Akihiko Yamaguchi, Hajime Kitano, Akio Shimizu, Jae Man Lee, Takahiro Kusakabe, Michiya Matsuyama
    Abstract:

    The Pituitary Gonadotropins (GtHs), follicle-stimulating hormone (FSH) and luteinizing hormone (LH), are key regulators of gametogenesis in teleosts. However, little is known about the physiological mechanisms by which GtHs regulate asynchronous oocyte development in multiple-spawning marine fishes. We cloned cDNAs encoding GtH receptors (FSHR and LHR) from chub mackerel (Scomber japonicus). FSH and LH were purified by anion-exchange chromatography, gel filtration, and concanavalinA-agarose. When expressed in mammalian cells, FSHR and LHR responded strongly to their own ligands. By separating LH into two subunits by the use of reverse-phase chromatography, we found that the beta-subunit is responsible for signal transduction and the alpha-subunit may be important for holding hormone-receptor complex. In situ hybridization showed that only fshr was expressed in prefollicle and granulosa cells in oocytes at the perinucleolus and cortical alveolus stages, suggesting that FSH is involved in the primary and early secondary growth of oocytes. In ovarian follicles during vitellogenesis, both fshr and lhr were expressed in granulosa and thecal cells, and lhr was strongly expressed during germinal vesicle migration (GVM). Real-time PCR analysis of stage-dependent fshr and lhr expression showed that fshr expression was high in ovarian follicles throughout vitellogenesis and decreased during GVM, whereas lhr expression was low in early vitellogenesis, but increased markedly in the late phase of vitellogenesis, remaining high during GVM. These findings suggest that switching of the expression of FSHR to LHR controls the effects of FSH and/or LH on vitellogenesis and final oocyte maturation via steroid production in granulosa and thecal cells.

  • Immunoreactive changes in Pituitary FSH and LH cells during seasonal reproductive and spawning cycles of female chub mackerel Scomber japonicus
    Fisheries Science, 2011
    Co-Authors: Mitsuo Nyuji, Sethu Selvaraj, Akihiko Yamaguchi, Tetsuro Shiraishi, Vu In, Hajime Kitano, Kumiko Okamoto, Shizumasa Onoue, Akio Shimizu, Michiya Matsuyama
    Abstract:

    The physiological functions of Pituitary Gonadotropins (GtHs) are well established in higher vertebrates, whereas those in teleosts are still poorly understood. To describe the role of GtHs during gonadal development of female chub mackerel Scomber japonicus , changes in follicle-stimulating hormone (FSH) and luteinizing hormone (LH) cells were investigated immunohistochemically during the seasonal reproductive and spawning cycles. FSH and LH cells were identified in the different cell types of the proximal pars distalis (PPD); FSH cells were located in the central PPD, whereas LH cells were localized along the border of the pars intermedia. To examine changes in FSH and LH cells, the percentage of FSH or LH cell-occupying area in the PPD was evaluated and represented as FSHβ-immunoreactive (ir) or LHβ-ir levels, respectively. FSHβ-ir levels increased significantly from immature to the completion of vitellogenesis, whereas LHβ-ir levels were maintained at high levels from early vitellogenesis to post-spawning. During the spawning cycle, which consisted of four stages from just after spawning to the next oocyte maturation, both FSHβ-ir and LHβ-ir levels showed no significant changes among different stages; however, LHβ-ir levels remained relatively high, and FSHβ-ir levels were constantly low. These results suggest that both FSH and LH may be involved in vitellogenesis and LH may act at final oocyte maturation in female chub mackerel, although the role of FSH during the spawning cycle is still unclear.

  • sexually dimorphic expression of Pituitary glycoprotein hormones in a sex changing fish pseudolabrus sieboldi
    Journal of Experimental Zoology, 2008
    Co-Authors: Akihiko Yamaguchi, Kohei Ohta, Takayuki Mine, Michiya Matsuyama
    Abstract:

    It is widely accepted that the hypothalamic–Pituitary–gonadal axis is involved in gonadal sex change in socially controlled sex-changing fish. However, the specific secretion profiles of Pituitary Gonadotropins (GtHs) in this type of fish are not known. To address this fundamental question, we demonstrated that the diurnal secretion patterns of GtHs differ distinctly between males and females in a socially controlled sex-changing fish. We analyzed the Pituitary mRNA levels of glycoprotein hormone subunits (i.e., the common α-subunit and specific β-subunits follicle-stimulating hormone β, luteinizing hormone β, and thyroid-stimulating hormone β) in the wrasse Pseudolabrus sieboldi, which is a model fish that exhibits accurate diurnal rhythms of gametogenesis in both males and females. Northern blots clearly showed that each subunit gene exhibits a diurnal rhythm of expression in the Pituitary and that the expression patterns differ distinctly between the sexes. Our results suggest that oogenesis and spermatogenesis in this hermaphroditic fish are regulated differentially through the distinct secretion patterns of Pituitary glycoprotein hormones. This study also provides direct evidence of the sexual plasticity of Pituitary GtH secretion in a socially controlled sex-changing fish. J. Exp. Zool. 309A:534–541, 2008. © 2008 Wiley-Liss, Inc.