Novel fish hypothalamic neuropeptides stimulate the release of gonadotrophins and growth hormone from the pituitary of sockeye salmon

Amano, Masafumi; Moriyama, Shunsuke; Iigo, Masayuki; Kudoh, Shoji; Amiya, Noriko; Yamamori, Kunio; Ukena, Kazuyoshi; Tsutsui, Kazuyoshi

doi:10.1677/joe.1.06494

Cited by 119 publications

(142 citation statements)

References 21 publications

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“…Considering the changes in GnIH mRNA during reproduction, we concluded that GnIH plays a negative role in regulating GtH in the common carp. The results are consistent to those for the zebrafish and goldfish (Qi et al, 2013;Zhang et al, 2010), but opposite to the results obtained for the grass puffer, tilapia, and salmon (Amano et al, 2006;Biran et al, 2014;Shahjahan et al, 2011). The differing results may be related to the protein sequence of common carp GnIH compared with those of the goldfish, zebrafish, grass puffer, and tilapia.…”

Section: Discussionsupporting

confidence: 43%

“…These results indicate the negative regulation of GnIH on GtH. However, when incubating sockeye salmon (Oncorhynchus nerka) pituitary cell with different doses of goldfish GnIH-I/II/III peptides, FSH, LH, and GH concentrations increased significantly (Amano et al, 2006). In the grass puffer (Takifugu niphobles), incubation of pituitary cells with different doses of goldfish GnIH-I resulted in an increase in FSH and LH mRNA levels (Shahjahan et al, 2011).…”

Section: Introductionmentioning

confidence: 91%

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GnIH plays a negative role in regulating GtH expression in the common carp, Cyprinus carpio L.

Wei

Cao

Chen

et al. 2016

General and Comparative Endocrinology

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a b s t r a c tIn birds and mammals, the gonadotrophin-inhibitory hormone (GnIH) effectively inhibits the expression of gonadotrophin (GtH). In teleosts, the effects of GnIH are still unclear and under much debate. The aim of this study is to evaluate the functions of GnIH/receptors of gonadotrophin-inhibitory hormone (GnIHRs) system during reproduction in the common carp, Cyprinus carpio L. We cloned the full cDNA sequences of GnIH /GnIHRs. Real-time PCR results showed that GnIH/GnIHRs were distributed extensively across the whole hypothalamus-pituitary-gonad (HPG) axis. We also examined the changes of GnIH/GnIHRs in the HPG axis during reproduction. GnIH mRNA expression was decreased to the minimum value in Apr, the spawning month, and increased immediately after the completion of reproduction. Expression pattern of GnIH during reproduction was the opposite to those of Gonadotrophin release hormone 3 (GnRH3) and luteinizing hormone (LH). Expression patterns of GnIHRs were similar to that of GnIH in the hypothalamus. In the pituitary, GnIHR2/3 peaked in March before spawning. In the ovaries, the GnIHR1 decreased to the minimum value in April, but GnIHR2/3 increased. By injection and incubation with synthesized GnIH-III peptide, we confirmed the negative influence of GnIH on mRNAs of the follicle-stimulating hormone-b and LH-b subunits in the common carp. These results show that the GnIH/GnIHRs system is involved in the negative regulation of reproduction in HPG axis of the common carp.

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Section: Discussionsupporting

confidence: 43%

Section: Introductionmentioning

confidence: 91%

GnIH plays a negative role in regulating GtH expression in the common carp, Cyprinus carpio L.

Wei

Cao

Chen

et al. 2016

General and Comparative Endocrinology

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“…Similarly, the rat GnIH ortholog RFRP3 increases the levels of GH in plasma (Johnson et al 2007). In teleosts, gGnIH and the other two putative RFamide peptides stimulate the release of GH from cultured pituitary cells from male sockeye salmon (Amano et al 2006).…”

Section: Introductionmentioning

confidence: 98%

“…Goldfish (g) GnIH (LPXRFamide 3) exerts both stimulatory and inhibitory influences on basal goldfish gonadotrope functions in a season-dependent manner, as well as differentially modulating the effects of sGnRH-and cGnRHII-induced gonadotrope functions (Moussavi et al , 2013. On the other hand, zebrafish GnIH reduced serum LH levels in adult goldfish (Zhang et al 2010), whereas gGnIH elevated LH and FSH release from salmon pituitary cell cultures (Amano et al 2006).…”

Section: Introductionmentioning

confidence: 99%

Seasonal effects of GnIH on basal and GnRH-induced goldfish somatotrope functions

Moussavi¹,

Wlasichuk²,

Chang³

et al. 2014

Journal of Endocrinology

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To understand how gonadotropin-inhibitory hormone (GnIH) regulates goldfish GH cell functions, we monitored GH release and expression during early, mid-, and/or late gonadal recrudescence. In vivo and in vitro responses to goldfish (g) GnIH were different, indicating direct action at the level of pituitary, as well as interactions with other neuroendocrine factors involved in GH regulation. Injection of gGnIH consistently reduced basal serum GH levels but elevated pituitary gh mRNA levels, indicating potential dissociation of GH release and synthesis. Goldfish GnRH (sGnRH and cGnRHII) injection differentially stimulated serum GH and pituitary gh mRNA levels with some seasonal differences; these responses were reduced by gGnIH. In contrast, in vitro application of gGnIH during 24-h static incubation of goldfish pituitary cells generally elevated basal GH release and attenuated sGnRH-induced changes in gh mRNA, while suppressing basal gh mRNA levels at mid-and late recrudescence but elevating them at early recrudescence. gGnIH attenuated the GH release responses to sGnRH during static incubation at early, but not at mid-and late recrudescence. In cell column perifusion experiments examining short-term GH release, gGnIH reduced the cGnRHII-and sGnRH-stimulated secretion at late recrudescence but inhibited tha action of cGnRHII only during mid-recrudescence. Interestingly, a reduction of basal GH release upon perifusion with gGnIH during late recrudescence was followed by a rebound increase in GH release upon gGnIH removal. These results indicate that gGnIH exerts complex effects on basal and GnRH-stimulated goldfish GH cell functions and can differentially affect GH release and mRNA expression in a seasonal reproductive manner.

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“…We therefore designated this neuropeptide as gonadotropin-inhibitory hormone (GnIH; Tsutsui et al 2000). Subsequently, several neuropeptides which were closely related to GnIH were identified in the brains of other vertebrates, such as mammals (RFamide-related peptides (RFRPs), Fukusumi et al 2001, Yoshida et al 2003, Ubuka et al 2009a, frogs (frog GH-releasing peptide (fGRP), Koda et al 2002, Ukena et al 2003b; Rana RFamide (R-RFa), Chartrel et al 2002) and fish (goldfish (gf) LPXRFa, Sawada et al 2002b, Amano et al 2006. Thus, it is becoming clear that GnIH and its orthologs having a common C-terminal LPXRFa motif (LPXRFa peptides) are synthesized in the brain in a variety of vertebrates (for reviews, see , Tsutsui 2009, 2010, Tsutsui & Osugi 2009, Tsutsui et al 2010a.…”

Section: Introductionmentioning

confidence: 99%

Identification, localization and expression of LPXRFamide peptides, and melatonin-dependent induction of their precursor mRNA in the newt brain

Chowdhury¹,

Ubuka²,

Osugi³

et al. 2011

Journal of Endocrinology

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The existence of RFamide peptides with a C-terminal LPXRFamide (XZL or Q) motif has been identified in the brain of various vertebrate species. However, the presence of LPXRFamide peptides in the urodele brain is not yet known. In this study, we cloned a cDNA encoding the precursor of LPXRFamide peptides from the newt brain by a combination of 3 0 and 5 0 rapid amplification of cDNA ends. The deduced LPXRFamide peptide precursor consisted of 233 amino acid residues, encoding four putative LPXRFamide peptides. All the peptide sequences were flanked by a glycine C-terminal amidation signal and basic amino acid on each end as an endoproteolytic site. Mass spectrometric analyses detected a nonapeptide, two decapeptides and an octapeptide produced from the precursor polypeptide in the brain as endogenous ligands. In situ hybridization further revealed the cellular localization of newt LPXRFamide (nLPXRFa) precursor mRNA in the suprachiasmatic nucleus (SCN) in the newt hypothalamus. Immunocytochemistry showed a cluster of cell bodies restricted to the SCN and their terminals in the median eminence. To understand the regulatory mechanism of nLPXRFa peptide expression, we further analyzed the effect of melatonin on the expression of nLPXRFa precursor mRNA. Melatonin administration to newts increased the expression of nLPXRFa precursor mRNA in the diencephalon. These results indicate that the urodele hypothalamus possesses LPXRFamide peptides and the expression of LPXRFamide peptides is regulated by melatonin. The localization of nLPXRFa peptides further suggests that these peptides may be involved in the regulation of pituitary hormone release in newts.

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Novel fish hypothalamic neuropeptides stimulate the release of gonadotrophins and growth hormone from the pituitary of sockeye salmon

Cited by 119 publications

References 21 publications

GnIH plays a negative role in regulating GtH expression in the common carp, Cyprinus carpio L.

GnIH plays a negative role in regulating GtH expression in the common carp, Cyprinus carpio L.

Seasonal effects of GnIH on basal and GnRH-induced goldfish somatotrope functions

Identification, localization and expression of LPXRFamide peptides, and melatonin-dependent induction of their precursor mRNA in the newt brain

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