Seasonal Effect of Gonadotrophin Inhibitory Hormone on <scp>Gonadotrophin‐Releasing Hormone</scp>‐induced Gonadotroph Functions in the Goldfish Pituitary

Moussavi, Mina; Wlasichuk, M.; Chang, John P.; Habibi, Hamid R.

doi:10.1111/jne.12024

Cited by 78 publications

(85 citation statements)

References 56 publications

(106 reference statements)

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“…Primary pituitary cell static culture The cell culture protocol and methodology were consistent with those used in our previous investigations (Moussavi et al , 2013. Cells in static incubation cultures were treated continuously with stimuli for 12-h. At the end of incubation, medium samples were collected and frozen at K20 8C for RIA, and cells were used for RNA extraction.…”

Section: Methodsmentioning

confidence: 99%

“…Goldfish acclimatization protocol, water temperature, diet, gonadal somatic index, and handling have been described previously by our group (Moussavi et al , 2013. All protocols involving animals were approved by the appropriate university animal care committees in accordance with the principles and guidelines of the Canadian Council on Animal Care.…”

Section: Methodsmentioning

confidence: 99%

“…Pituitary RNA extraction and quantitative real-time PCR Total RNA was extracted using TRIzol Reagent (Invitrogen) according to the manufacturer's protocol as described previously (Moussavi et al , 2013. Owing to the low RNA concentrations obtained from a single pituitary, two to three individual pituitaries were pooled for RNA extraction and subsequently used for quantitative real-time PCR (qPCR), using b-actin as an internal control.…”

Section: Methodsmentioning

confidence: 99%

“…PBS (0 mg). Individual goldfish each received two injections according to the established procedure (Chang & Peter 1983), initially at 0-h and later at 12-h as described previously (Moussavi et al , 2013. At 2-h post-second-injection, blood was collected and serum samples were stored at K20 8C for later GH RIA, as described previously (Marchant et al 1987).…”

Section: Methodsmentioning

confidence: 99%

“…Immunoreactive GnIH has also been detected in the pituitary of Indian major carp (Biswas et al 2014); however, recent work on teleosts has revealed that GnIH control of gonadotrope activities is complex and not always inhibitory. 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%

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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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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

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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LPXRFa peptide system in the European sea bass: A molecular and immunohistochemical approach

Paullada-Salmerón

Cowan

Aliaga-Guerrero

et al. 2015

J of Comparative Neurology

105

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Gonadotropin-inhibitory hormone (GnIH) is a neuropeptide that suppresses reproduction in birds and mammals by inhibiting GnRH and gonadotropin secretion. GnIH orthologs with a C-terminal LPXRFamide (LPXRFa) motif have been identified in teleost fish. Although recent work also suggests its role in fish reproduction, studies are scarce and controversial, and have mainly focused on cyprinids. In this work we cloned a full-length cDNA encoding an LPXRFa precursor in the European sea bass, Dicentrarchus labrax. In contrast to other teleosts, the sea bass LPXRFa precursor contains only two putative RFamide peptides, termed sbLPXRFa1 and sbLPXRFa2. sblpxrfa transcripts were expressed predominantly in the olfactory bulbs/telencephalon, diencephalon, midbrain tegmentum, retina, and gonads. We also developed a specific antiserum against sbLPXRFa2, which revealed sbLPXRFa-immunoreactive (ir) perikarya in the olfactory bulbs-terminal nerve, ventral telencephalon, caudal preoptic area, dorsal mesencephalic tegmentum, and rostral rhombencephalon. These sbLPXRFa-ir cells profusely innervated the preoptic area, hypothalamus, optic tectum, semicircular torus, and caudal midbrain tegmentum, but conspicuous projections also reached the olfactory bulbs, ventral/dorsal telencephalon, habenula, ventral thalamus, pretectum, rostral midbrain tegmentum, posterior tuberculum, reticular formation, and viscerosensory lobe. The retina, pineal, vascular sac, and pituitary were also targets of sbLPXRFa-ir cells. In the pituitary, this innervation was observed close to follicle-stimulating hormone (FSH), luteinizing hormone (LH) and growth hormone (GH) cells. Tract-tracing retrograde labeling suggests that telencephalic and preoptic sbLPXRFa cells might represent the source of pituitary innervation. The immunohistochemical distribution of sbLPXRFa cells and fibers suggest that LPXRFa peptides might be involved in some functions as well as reproduction, such as feeding, growth, and behavior.

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Distribution of LPXRFa, a gonadotropin‐inhibitory hormone ortholog peptide, and LPXRFa receptor in the brain and pituitary of the tilapia

Ogawa

Sivalingam

Biran

et al. 2016

J of Comparative Neurology

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In vertebrates, gonadotropin-releasing hormone (GnRH) and gonadotropin-inhibitory hormone (GnIH), respectively, regulate reproduction in positive and negative manners. GnIH belongs to the LPXRFa family of peptides previously identified in mammalian and nonmammalian vertebrates. Studying the detailed distribution of LPXRFa as well as its receptor (LPXRFa-R) in the brain and pituitary is important for understanding their multiple action sites and potential functions. However, the distribution of LPXRFa and LPXRFa-R has not been studied in teleost species, partially because of the lack of fish-specific antibodies. Therefore, in the present study, we generated specific antibodies against LPXRFa and its receptor from Nile tilapia (Oreochromis niloticus), and examined their distributions in the brain and pituitary by immunohistochemistry. Tilapia LPXRFa-immunoreactive neurons lie in the posterior ventricular nucleus of the caudal preoptic area, whereas LPXRFa-R-immunoreactive cells are distributed widely. Double immunofluorescence showed that neither LPXRFa-immunoreactive fibers nor LPXRFa-R is closely associated or coexpressed with GnRH1, GnRH3, or kisspeptin (Kiss2) neurons. In the pituitary, LPXRFa fibers are closely associated with gonadotropic endocrine cells [expressing luteinizing hormone (LH) and follicle-stimulating hormone (FSH)], with adrenocorticomelanotropic cells [corticotropin (ACTH) and α-melanotropin (α-MSH)], and with somatolactin endocrine cells. In contrast, LPXRFa-R are expressed only in LH, ACTH, and α-MSH cells. These results suggest that LPXRFa and LPXRFa-R signaling acts directly on the pituitary cells independent from GnRH or kisspeptin and could play multiple roles in reproductive and nonreproductive functions in teleosts. J. Comp. Neurol. 524:2753-2775, 2016. © 2016 Wiley Periodicals, Inc.

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Seasonal Effect of Gonadotrophin Inhibitory Hormone on Gonadotrophin‐Releasing Hormone‐induced Gonadotroph Functions in the Goldfish Pituitary

Cited by 78 publications

References 56 publications

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

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

LPXRFa peptide system in the European sea bass: A molecular and immunohistochemical approach

Distribution of LPXRFa, a gonadotropin‐inhibitory hormone ortholog peptide, and LPXRFa receptor in the brain and pituitary of the tilapia

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