Gonadotropin-releasing hormone (GnRH) in bony fish that are phylogenetically ancient: Reedfish (Calamoichthys calabaricus), sturgeon (Acipenser transmontanus), and alligator gar (Lepisosteus spatula)

Sherwood, Nancy M.; Doroshov, Serge I.; Lance, V. A.

doi:10.1016/0016-6480(91)90063-c

Cited by 81 publications

(17 citation statements)

References 24 publications

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“…Immunoreactive GnRH was seen as brown granular reaction product in the cytoplasm and processes of certain neurons. Specificities and crossreactivities of primary antisera (salmon-, mammalian-, and chicken II-GnRH) used in this study have been verified with heterologous and homologous forms of GnRHs and with various neuropeptides (Kelsall et al, 1990;Sherwood et al, 1991;Muske and Moore, 1994;Parhar et al, 1996a). Omission or absorption of the primary antisera at the working dilution with 1 µg/ml of salmon-, mammalian-, or chicken II-GnRH blocked all immunoreactivity.…”

Section: Immunohistochemistrymentioning

confidence: 99%

Neurons synthesizing gonadotropin-releasing hormone mRNA subtypes have multiple developmental origins in the medaka

Parhar

Soga

Ishikawa³

et al. 1998

J. Comp. Neurol.

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The origins of the different populations of gonadotropin-releasing hormone (GnRH)-containing neurons in the brains of two genotypes (HO4C; HNI-II) of medaka Oryzias latipes were analyzed at different stages of development (day 1 after fertilization through adulthood), by using oligonucleotide probes specific to salmon-, seabream-, and chicken II-GnRH mRNA and antisera against specific GnRH peptides. Between the two genotypes, there was no difference in the site and time of GnRH expression or the final pattern of GnRH neuronal organization. In the adult fish of both sexes, salmon GnRH mRNA and peptide-containing neurons were seen in the terminal nerve ganglia (nucleus olfactoretinalis; NOR) and chicken II-GnRH mRNA and peptide-containing neurons in the midbrain tegmentum. GnRH cells at the base of the olfactory placode (1-2 cells) and in the midbrain tegmentum were first seen in 1-day-old fish of both genotypes. On day 15, lightly immunoreactive GnRH cells were seen in the NOR of only HNI genotype. By day 30, GnRH expression in the NOR and in the midbrain was prominent. GnRH cells along the basal olfactory bulb and basal telencephalon were occasionally seen in animals 30 days or older. This developmental study shows differential distribution of salmon and chicken II-GnRH mRNA subtypes and emphasizes their separate embryonic origins from the olfactory apparatus (salmon-GnRH) and the ependymal cells of the third ventricle (chicken II-GnRH). The absence of preoptic GnRH hybridization signals, immunoreactivity and the lack of GnRH fibers in the pituitary suggests that the preoptic GnRH neurons are distinct from the olfactory derived-terminal nerve GnRH neurons, and that the GnRH neurites reported in the pituitary of teleost must be of preoptic origin.

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Section: Immunohistochemistrymentioning

confidence: 99%

Neurons synthesizing gonadotropin-releasing hormone mRNA subtypes have multiple developmental origins in the medaka

Parhar

Soga

Ishikawa³

et al. 1998

J. Comp. Neurol.

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“…cGnRH-II is universally distributed in bony fish (1). In addition to cGnRH-II, mGnRH is found in lobe-finned fish (19), the ancient ray-finned bony fish that evolved before the teleosts (20,21), and in teleosts that evolved early such as Pantodon (22) and eels (23). All other teleosts studied to date have salmon GnRH with the exception of catfish, which has cfGnRH (15).…”

Section: G Nrh Is a Key Neurohormone For Reproduction In Allmentioning

confidence: 99%

Primary Structure of a Novel Gonadotropin-Releasing Hormone in the Brain of a Teleost, Pejerrey

Montaner¹

2001

Endocrinology

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The neuropeptide GnRH is the major regulator of reproduction in vertebrates acting as a first signal from the hypothalamus to pituitary gonadotropes. Three GnRH molecular variants were detected in the brain of a fish, pejerrey (Odontesthes bonariensis), using chromatographic and immunological methods. The present study shows that one form is identical to chicken GnRH-II (sequence analysis and mass spectrometry) and the second one is immunologically and chromatographically similar to salmon GnRH. The third form was proven to be a novel form of GnRH by isolating the peptide from the brain and determining its primary structure by chemical sequencing and mass spectrometry. The sequence of the novel pejerrey GnRH is pGlu-HisTrp-Ser-Phe-Gly-Leu-Ser-Pro-Gly-NH 2 , which is different from the known forms of the vertebrate and protochordate GnRH family. The new form of GnRH is biologically active in releasing gonadotropin and GH from pituitary cells in an in vitro assay. (Endocrinology 142:

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“…It is known that the sturgeon brain secretes mammalian-type GnRH (Sherwood et al 1991), but the sites of secretion and interaction of GnRH with pituitary gonadotropes have not been identified. Studies in our laboratory with white sturgeon,Acipenser transmontanus have shown the gonadotropin releasing hormone analog D-Ala 6 -des-Gly' 0 -GnRH ethylamide (GnRHa) to be an effective stimulant for the release of two gonadotropins, termed sturgeon gonadotropin I (stGTH I) and sturgeon gonadotropin II (st GTH II) (Moberg et al 1991a(Moberg et al , 1995.…”

Section: Introductionmentioning

confidence: 99%

Dopaminergic influence on gonadotropin secretion in white sturgeon (Acipenser transmontanus)

Pavlick

Moberg

1997

Fish Physiol Biochem

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The effects of dopamine on the secretion of two sturgeon gonadotropins (stGTH I and stGTH II) in sexually mature male white sturgeon (Acipenser transmontanus) were evaluated. In Experiment I, sturgeon were given intraperitoneal injections of physiological saline (PS), dopamine (100 mg kg-'), the gonadotropin releasing hormone analog D-Ala 6 -des-Gly 10 -GnRH ethylamide (GnRHA) (10 jig/kg-'), and a combination of GnRHa and dopamine. Fish receiving only GnRHa had significantly higher (p < 0.05) concentrations of plasma stGTH I and stGTH II compared to fish receiving PS, dopamine, or a combination of GnRHa and dopamine. Two hours following its administration, dopamine was effective in decreasing plasma concentrations of both stGTHs that were previously elevated by GnRHa. Dopamine or PS administered by themselves did not alter plasma concentrations of either stGTH. In Experiment II, sturgeon injected intraperitoneally with a combination of GnRHa and pimozide had significantly higher (p < 0.05) concentrations of plasma stGTH I and stGTH II compared to males receiving GnRHa or pimozide alone. While this effect of GnRHAa + pimozide was observed in the spring, no such potentiation was seen in these fish during the summer (Experiment III). These results represent the first evidence of dopaminergic inhibition of GnRH-induced pituitary gonadotropin secretion in Chondrostean fish.

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Gonadotropin-releasing hormone (GnRH) in bony fish that are phylogenetically ancient: Reedfish (Calamoichthys calabaricus), sturgeon (Acipenser transmontanus), and alligator gar (Lepisosteus spatula)

Cited by 81 publications

References 24 publications

Neurons synthesizing gonadotropin-releasing hormone mRNA subtypes have multiple developmental origins in the medaka

Neurons synthesizing gonadotropin-releasing hormone mRNA subtypes have multiple developmental origins in the medaka

Primary Structure of a Novel Gonadotropin-Releasing Hormone in the Brain of a Teleost, Pejerrey

Dopaminergic influence on gonadotropin secretion in white sturgeon (Acipenser transmontanus)

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