Role of GnRH, HCG and Kisspeptin on Reproduction of Fishes

Elakkanai, P.; Francis, T.; Ahilan, B.; Jawahar, P.; Padmavathy, P.; Jayakumar, N.; Subburaj, Anitha Sarah

doi:10.17485/ijst/2015/v8i17/65166

Cited by 21 publications

(15 citation statements)

References 70 publications

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“…The kisspeptins are a family of neuropeptides which act as upstream stimulators of GnRH neurons ( 59 ). More specifically, kisspeptins appear to play an important role in determining seasonality of reproduction, transducing the feedback effect of gonadal steroids as well as having an independent (non-steroid dependent) circannual rhythm ( 58 , 60 – 62 ). The KiSS genes have been identified in most vertebrates and fish, which may have up to three Kiss genes ( 63 ).…”

Section: Mechanism Of Actions Of Melatonin As a Hormone In The Regulamentioning

confidence: 99%

The Role of Melatonin as a Hormone and an Antioxidant in the Control of Fish Reproduction

Maitra

Hasan

2016

Front. Endocrinol.

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Reproduction in most fish is seasonal or periodic, and the spawning occurs in an appropriate season to ensure maximum survival of the offspring. The sequence of reproductive events in an annual cycle is largely under the control of a species-specific endogenous timing system, which essentially relies on a well-equipped physiological response mechanism to changing environmental cues. The duration of solar light or photoperiod is one of the most predictable environmental signals used by a large number of animals including fish to coordinate their seasonal breeding. In vertebrates, the pineal gland is the major photoneuroendocrine part of the brain that rhythmically synthesizes and releases melatonin (N-acetyl-5-methoxytryptamine) into the circulation in synchronization with the environmental light–dark cycle. Past few decades witnessed an enormous progress in understanding the mechanisms by which melatonin regulates seasonal reproduction in fish and in other vertebrates. Most studies emphasized hormonal actions of melatonin through its high-affinity, pertussis toxin-sensitive G-protein (guanine nucleotide-binding protein)-coupled receptors on the hypothalamus–pituitary–gonad (HPG) axis of fish. However, the discovery that melatonin due to its lipophilic nature can easily cross the plasma membrane of all cells and may act as a potent scavenger of free radicals and stimulant of different antioxidants added a new dimension to the idea explaining mechanisms of melatonin actions in the regulation of ovarian functions. The basic concept on the actions of melatonin as an antioxidant emerged from mammalian studies. Recently, however, some new studies clearly suggested that melatonin, apart from playing the role of a hormone, may also be associated with the reduction in oxidative stress to augment ovarian functions during spawning. This review thus aims to bring together the current knowledge on the role of melatonin as a hormone as well as an antioxidant in the control of fish reproduction and shape the current working hypotheses supported by recent findings obtained in carp or based on knowledge gathered in mammalian and avian species. In essence, this review highlights potential actions of melatonin as a hormone in determining temporal pattern of spawning and as an antioxidant in regulating oocyte maturation at the downstream of HPG axis in fish.

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Section: Mechanism Of Actions Of Melatonin As a Hormone In The Regulamentioning

confidence: 99%

The Role of Melatonin as a Hormone and an Antioxidant in the Control of Fish Reproduction

Maitra

Hasan

2016

Front. Endocrinol.

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“…The role of exogenous hormones on reproduction of teleosts has been studied and reviewed in order to ensure adequate milt production for artificial propagation (Elakkanai et al 2015). In Vietnam, LHRHa, HCG, and DOM, are traditional agents for ovulation and spermiation induction in females and males of marine or freshwater fish species.…”

Section: Discussionmentioning

confidence: 99%

“…Several hormones are available and have been commonly studied in many fish species (Mañanós et al 2009). Moreover, spermiation and ovulation in many marine fish species can be improved or increased following exogenous hormone stimulation, mainly human chorionic gonadotropin (HCG), luteinizing hormone releasing hormone analog (LHRHa), and domperidone (DOM) (Elakkanai et al 2015). The results of these studies showed that proper hormonal stimulation in female fish is speciesspecific, but can be used for induction of male sperimation for all species.…”

Section: Introductionmentioning

confidence: 99%

Effects of Time after Hormonal Stimulation on Milt Properties in Waigieu Seaperch Psammoperca waigiensis

Le¹,

Brown²

2016

Israeli Journal of Aquaculture - Bamidgeh

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As from January 2010 The Israeli Journal of Aquaculture-Bamidgeh (IJA) will be published exclusively as an on-line Open Access (OA) quarterly accessible by all AquacultureHub (http://www.aquaculturehub.org) members and registered individuals and institutions. Please visit our website (http://siamb.org.il) for free registration form, further information and instructions. This transformation from a subscription printed version to an on-line OA journal, aims at supporting the concept that scientific peer-reviewed publications should be made available to all, including those with limited resources. The OA IJA does not enforce author or subscription fees and will endeavor to obtain alternative sources of income to support this policy for as long as possible.

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“…Owing to less availability of fish gonadotropins, studies related to gonadotropic regulation of fish reproduction have mainly relied on mammalian gonadotropins. Among these hormones, human chorionic gonadotropin (hCG) is commonly used in aquaculture and is highly potent in inducing steroidogenesis and gametogenesis in several fishes (Elakkanai et al, 2015). Taking this into consideration, the present study was aimed at identification and in silico analysis of Fshra and Lhcgr, estimation of messenger RNA (mRNA) levels of fshra and lhcgr in testis during different reproductive phases and hCG regulation of their testicular mRNA expression in a seasonally breeding freshwater teleost spotted snakehead Channa punctata (Bloch 1793) belonging to the order Perciformes.…”

Section: Introductionmentioning

confidence: 99%

In silico analysis, temporal expression and gonadotropic regulation of receptors for follicle‐stimulating hormone and luteinizing hormone in testis of spotted snakehead Channa punctata

Basak

Roy

Rai

2018

Journal of Fish Biology

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This study in spotted snakehead Channa punctata was aimed to develop a comprehensive understanding of testicular gonadotropin receptors, from their sequence characterization, temporal expression to gonadotropic regulation, in seasonally breeding teleosts. A single form of follicle-stimulating hormone receptor (cpfshra) and luteinizing hormone/choriogonadotropin receptor (cplhcgr), was identified from testicular transcriptome data of C. punctata. Although deduced full-length protein sequence for cpFshra (694 amino acids) and cpLhcgr (691 amino acids) showed homology with their counterparts of other vertebrates, multiple insertion-deletion-substitution of residues suggest marked alterations in their structure and ligand specificity. The absolute quantification of testicular cpfshra and cplhcgr was estimated along the reproductive cycle following real-time PCR. The temporal expression profile showed highest testicular expression of both the gonadotropin receptors during resting phase. Their expression progressively decreased during preparatory and spawning phases concomitant with spermatogonial proliferation and differentiation and spermiogenesis. However, levels of cpfshra and cplhcgr sharply increased during post-spawning when seminiferous lobules were largely devoid of germ cells. To explore gonadotropic regulation of testicular cpfshra and cplhcgr, one group of fish of resting phase was administered with single dose of human chorionic gonadotropin (hCG; 5,000 IU/kg body mass) on day 0 and sacrificed on day 3 and day 5, while another group receiving two injections of hCG (day 0 and day 7) was sacrificed on day 14. The expression pattern of testicular gonadotropin receptors in hCG-treated fish sacrificed after 3, 5 and 14 days was similar to that of preparatory, spawning and postspawning phases, respectively. Likewise, testicular histology of hCG-treated fish sacrificed on day 3, day 5 and day 14 was comparable with that of preparatory, early spawning and late spawning phases, respectively. In light of the fact that gonadotropin receptors are largely expressed on somatic cells, an apparent decrease in testicular cpfshra and cplhcgr levels during preparatory and spawning phases or after 3 and 5 days from first hCG injection might not be due to downregulation of their expression. Rather, this could be due to dilution of somatic cell mRNA by large amount of germ cell mRNA. To verify this assumption, effect of hCG on plasma level of androgens was investigated employing enzyme-linked immunosorbent assay. A marked increase in plasma level of testosterone and 11-ketotestosterone was observed after hCG treatment in C. punctata. This would have been possible only when hCG upregulated the expression of testicular gonadotropin receptors.

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Role of GnRH, HCG and Kisspeptin on Reproduction of Fishes

Cited by 21 publications

References 70 publications

The Role of Melatonin as a Hormone and an Antioxidant in the Control of Fish Reproduction

The Role of Melatonin as a Hormone and an Antioxidant in the Control of Fish Reproduction

Effects of Time after Hormonal Stimulation on Milt Properties in Waigieu Seaperch Psammoperca waigiensis

In silico analysis, temporal expression and gonadotropic regulation of receptors for follicle‐stimulating hormone and luteinizing hormone in testis of spotted snakehead Channa punctata

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