In vitro characterization of gonadotropin-releasing hormone antagonists in goldfish, Carassius auratus

Murthy, C.K.

doi:10.1210/en.133.4.1633

Cited by 8 publications

(5 citation statements)

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“…Flett et al (1994) also reported that the [D-pGlu 1 , D-phe 2 , D-Trp 3,6 ] GnRH antagonist inhibited release of LH in response to the sGnRH analog from perifused pituitary glands of testosterone-primed immature rainbow trout. In goldfish, the GnRH antagonist used in this study was shown to block the sGnRH-and cGnRH-II-induced LH release from the pituitary fragments perifusion system (Murthy et al 1993). However, whether the GnRH antagonist acts directly at the pituitary cell level is not known.…”

Section: Discussionmentioning

confidence: 89%

The Control Mechanism of Gonadotropin-Releasing Hormone and Dopamine on Gonadotropin Release from Cultured Pituitary Cells of Rainbow Trout Oncorhynchus mykiss at Different Reproductive Stages

Kim¹,

Suzuki²,

Aida³

2011

Fisheries and aquatic sciences

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The mechanism by which gonadotropin-releasing hormone (GnRH) and dopamine (DA) control gonadotropin (GTH) release was studied in male and female rainbow trout using cultured pituitary cells obtained at different reproductive stages. The mechanisms of follicle-stimulating hormone (FSH) release by GnRH and DA could not be determined yet. However, basal and salmon-type GnRH (sGnRH)-or chicken-II-type GnRH (cGnRH-II)-induced luteinizing hormone (LH) release increased with gonadal maturation in both sexes. LH release activity was higher after sGnRH stimulation than cGnRH-II stimulation at maturing stages in both sexes. The GnRH antagonist ([Ac-3, 4-dehydro-Pro 1 , D-p-F-Phe 2 , D-Trp 3,6 ] GnRH) suppressed LH release by sGnRH stimulation in a dose-dependent manner, although the effect was weak in maturing fish. The role of DA as a GTH-release inhibitory factor differs during the reproductive cycle: the inhibition of sGnRH-stimulated LH release by DA was stronger in immature fish than in maturing, ovulating, or spermiated fish. DA did not completely inhibit sGnRH-stimulated LH release, and DA alone did not alter basal LH release. Relatively high doses (10 -6 or 10 -5 M) of domperidone (DOM, a DA D2 antagonist) increased LH release, which did not change with reproductive stage in either sex. The potency of DOM to enhance sGnRH-stimulated LH release was higher in maturing and ovulated fish than in immature fish. These data suggest that LH release from the pituitary gland is controlled by dual neuroendocrine mechanisms by GnRH and DA in rainbow trout, as has been reported in other teleosts. The mechanism of control of FSH release, however, remains unknown.

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Section: Discussionmentioning

confidence: 89%

The Control Mechanism of Gonadotropin-Releasing Hormone and Dopamine on Gonadotropin Release from Cultured Pituitary Cells of Rainbow Trout Oncorhynchus mykiss at Different Reproductive Stages

Kim¹,

Suzuki²,

Aida³

2011

Fisheries and aquatic sciences

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“…The ability to generate synthetic peptides and analogs prompted studies on the bioactivities of these two native GnRH isoforms present in goldfish, as well as of their analogs and antagonists. 28,29 Using primary pituitary cell culture and ex vivo perifusion, the ability of the different GnRHs to induce LH release was compared. 29 This study showed, for the first time, that cGnRHII is more potent than sGnRH in inducing LH release, whereas all peptides are equally potent in inducing growth hormone (GH) release.…”

Section: Fish Have Their Own Gnrh and More Than One!mentioning

confidence: 99%

“…60 In-depth peptide sequence and receptor binding analysis during this decade continued to lead to the development of many additional receptor agonists and antagonists based on teleost GnRHs. 28,31,61 Several compounds demonstrated preference for LH versus GH release. Translational applications of GnRH analogs for controlled spawning in aquaculture rapidly advanced during this period, further capitalizing on discoveries that happened in the previous decade.…”

Section: Gnrh Receptor Multiplicity: the Story Becomes More Complexmentioning

confidence: 99%

Section: The Decade Of 1981–1990mentioning

confidence: 99%

“…In‐depth peptide sequence and receptor binding analysis during this decade continued to lead to the development of many additional receptor agonists and antagonists based on teleost GnRHs 28,31,61 . Several compounds demonstrated preference for LH versus GH release.…”

Section: The Decade Of 1991–2000mentioning

confidence: 99%

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A half century of fish gonadotropin‐releasing hormones: Breaking paradigms

Zohar

Zmora

Trudeau

et al. 2021

J Neuroendocrinology

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The inception of the field of fish gonadotropin-releasing hormone (GnRH) biology is celebrating its 50th birthday and is only a few months younger than the seminal discovery of mammalian luteinizing hormone-releasing hormone (LHRH) in 1971. 1 During the same year, hypothalamic extracts were shown to stimulate the in vitro release of luteinizing hormone (LH) (formerly called fish gonadotropin or gonadotropin-II) in carp. 2 In 1973, synthetic LHRH and carp hypothalamic extracts were reported to elicit similar LH release in vivo in the same species. 3 It took 10 more years before Nancy M. Sherwood and her co-authors (1983) made the pioneering discovery that fish possess a unique GnRH, a decapeptide that is different from mammalian LHRH in two amino acids (now called GnRH1) (Figure 1). 4 Two years and 11 years later, respectively, fish were demonstrated to possess 2 and 3 GnRH isoforms. 5,6 The finding of GnRH multiplicity in fish created a paradigm shift and eventually led to the recognition that primates and humans also possess 2 GnRH isoforms. 7 As of today, we are still trying to fully understand the functional significance of GnRH multiplicity in vertebrates, albeit with significant progress over the last few years.The evolution and functions of fish GnRHs have been abundantly reviewed in recent years in a few excellent papers. [8][9][10][11][12] These reviews demonstrated how the understanding of fish GnRHs made

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Effects of a gonadotropin‐releasing hormone antagonist on gonadotropin levels in masu salmon and sockeye salmon

Amano¹,

Ikuta²,

Kudoh³

2007

J. Exp. Zool.

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The salmon gonadotropin-releasing hormone (sGnRH) is considered to be involved in gonadal maturation via gonadotropin (GTH) secretion in salmonid fishes. However, there is no direct evidence for endogenous sGnRH-stimulated GTH secretion in salmonids. In this study, to clarify whether endogenous sGnRH stimulates GTH secretion, we examined the effects of the mammalian GnRH (mGnRH) antagonist [Ac-Delta(3)-Pro(1), 4FD-Phe(2), D-Trp(3,6)]-mGnRH on luteinizing hormone (LH) levels in 0-year-old masu salmon Oncorhynchus masou and sockeye salmon Oncorhynchus nerka. First, the effects of the GnRH antagonist on LH release were examined in 0-year-old precocious male masu salmon. GnRH antagonist treatment for 3 hr significantly inhibited an increase in plasma LH levels that was artificially induced by exogenous sGnRH administration, indicating that the GnRH antagonist is effective in inhibiting LH release from the pituitary. Subsequently, we examined the effect of the GnRH antagonist on LH synthesis in 0-year-old immature sockeye salmon that were pretreated with exogenous testosterone for 42 days to increase the pituitary LH contents; the testosterone treatment did not affect the plasma LH levels. GnRH antagonist treatment slightly but significantly inhibited an increase in the testosterone-stimulated pituitary LH content levels. However, no significant differences in the plasma LH levels were observed between the GnRH antagonist-treated and control groups. These results suggest that endogenous sGnRH is involved in LH secretion in salmonid fishes.

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In vitro characterization of gonadotropin-releasing hormone antagonists in goldfish, Carassius auratus

Cited by 8 publications

References 0 publications

The Control Mechanism of Gonadotropin-Releasing Hormone and Dopamine on Gonadotropin Release from Cultured Pituitary Cells of Rainbow Trout Oncorhynchus mykiss at Different Reproductive Stages

The Control Mechanism of Gonadotropin-Releasing Hormone and Dopamine on Gonadotropin Release from Cultured Pituitary Cells of Rainbow Trout Oncorhynchus mykiss at Different Reproductive Stages

A half century of fish gonadotropin‐releasing hormones: Breaking paradigms

Effects of a gonadotropin‐releasing hormone antagonist on gonadotropin levels in masu salmon and sockeye salmon

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