Three GnRH systems in the brain and pituitary of a pleuronectiform fish, the barfin flounder Verasper moseri

Amano, Masafumi; Oka, Yoshitaka; Yamanome, Takeshi; Okuzawa, Koichi; Yamamori, Kunio

doi:10.1007/s00441-002-0594-z

Cited by 63 publications

(59 citation statements)

References 29 publications

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“…GtH then acts directly on the gonads to regulate reproductive hormone levels. Two or three unique GnRH variants have been identified in the central nervous system of some teleost fish (Somoza et al, 2002;Dubois et al, 2002;Nabissi et al, 2000;Amano et al, 2002). The Cyprinid fish family, to which the common carp belongs, has two forms of GnRH molecules: salmon GnRH (sGnRH) and chicken type-II GnRH (cGnRH-II; Penlington et al, 1997;Lin and Peter, 1996;Powell et al, 1996;Steven et al, 2003;Li et al, 2004aLi et al, , 2004b, which show regional differences in brain expression (e.g., the anterior parts of the cyprinid brain express more sGnRH than cGnRH-II; Yu et al, 1998).…”

Section: Introductionmentioning

confidence: 99%

Antisense for gonadotropin-releasing hormone reduces gonadotropin synthesis and gonadal development in transgenic common carp (Cyprinus carpio)

Tang

et al. 2007

Aquaculture

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Section: Introductionmentioning

confidence: 99%

Antisense for gonadotropin-releasing hormone reduces gonadotropin synthesis and gonadal development in transgenic common carp (Cyprinus carpio)

Tang

et al. 2007

Aquaculture

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“…In teleost fish, 8 GnRH variants have been identified, although two or three of the GnRH forms co-exist in the brain albeit distributed differently (Pham et al, 2006). Among the Pleuronectiforms and Perciformes, sea bream (sb)GnRH-producing cell bodies in the preoptic area project their axons mainly to the pituitary, whereas salmon sGnRHand chicken cGnRH-producing cells connect different areas of the brain through their axons, which, however, do not project to the pituitary (White et al, 1995;Gonzalez-Martínez et al, 2001;Amano et al, 2002).…”

mentioning

confidence: 99%

Brain morphology and immunohistochemical localization of the gonadotropin-releasing hormone in the bluefin tuna, Thunnus thynnus

Palmieri¹,

Acone²,

Desantis³

et al. 2009

Eur J Histochem

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The present study was focused on the morphology of the diencephalic nuclei (likely involved in reproductive functions) as well as on the distribution of GnRH (gonadotropin-releasing hormone) in the rhinencephalon, telencephalon and the diencephalon of the brain of bluefin tuna (Thunnus thynnus) by means of immunohistochemistry. Bluefin tuna has an encephalization quotient (QE) similar to that of other large pelagic fish. Its brain exhibits well-developed optic tecta and corpus cerebelli. The diencephalic neuron cell bodies involved in reproductive functions are grouped in two main nuclei: the nucleus preopticus-periventricularis and the nucleus lateralis tuberis. The nucleus preopticus-periventricularis consists of the nucleus periventricularis and the nucleus preopticus consisting of a few sparse multipolar neurons in the rostral part and numerous cells closely packed and arranged in several layers in its aboral part. The nucleus lateralis tuberis is located in the ventral-lateral area of the diencephalon and is made up of a number of large multipolar neurones. Four different polyclonal primary antibodies against salmon (s)GnRH, chicken (c)GnRH-II (cGnRH-II 675, cGnRH-II 6) and sea bream (sb)GnRH were employed in the immunohistochemical experiments. No immunoreactive structures were found with anti sbGnRH serum. sGnRH and cGnRH-II antisera revealed immunoreactivity in the perikarya of the olfactory bulbs, preopticus-periventricular nucleus, oculomotor nucleus and midbrain tegmentum. The nucleus lateralis tuberis showed immunostaining only with anti-sGnRH serum. Nerve fibres immunoreactive to cGnRH and sGnRH sera were found in the olfactory bulbs, olfactory nerve and neurohypophysis. The significance of the distribution of the GnRHimmunoreactive neuronal structures is discussed.

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Section: -2 Identification Of Gnrh Forms By Cdna Cloning In Barfin mentioning

confidence: 79%

“…cGnRH-II levels were high in the posterior part of the brain, especially in the medulla oblongata. Levels of sbGnRH were extremely low in all regions of the brain compared to those of sGnRH and cGnRH-II; sbGnRH was below the detectable limit in the cerebellum and the medulla oblongata (Amano et al 2002b).These results suggest that sGnRH and sbGnRH are involved in GTH secretion in masu salmon and barfin flounder, respectively. Judging from the wide distribution of sGnRH and cGnRH-II in the brain of masu salmon and barfin flounder, it is also suggested that sGnRH and cGnRH-II function as a neuromodulator in the brain.…”

mentioning

confidence: 73%

“…Indeed, some sbGnRH-ir fibers were in close apposition with GTH cells mainly in the PPD of the pituitary in a pleuronectiform fish Japanese flounder Paralichthys olivaceus (Pham et al 2007). It is also suggested that sGnRH and cGnRH-II function as neuromodulators in the brain, because both sGnRH-ir fibers and cGnRH-II-ir fibers were distributed widely in the brain but not in the pituitary (Amano et al 2002b). …”

Section: -2 Localization Of Gnrh Neurons In the Brainmentioning

confidence: 99%

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Reproductive Biology of Salmoniform and Pleuronectiform Fishes with Special Reference to Gonadotropin-Releasing Hormone (GnRH)

Amano¹

2010

Aqua-BioSci. Monogr. (ABSM)

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Keywords • GnRH AbstractA salmonid fish, masu salmon Oncorhynchus masou, has salmon gonadotropin-releasing hormone (sGnRH) and chicken GnRH-II (cGnRH-II), while a pleuronectiform fish, barfin flounder Verasper moseri, has sGnRH, cGnRH-II and seabream GnRH (sbGnRH). In masu salmon, sGnRH-immunoreactive (ir) cell bodies are scattered from the olfactory nerve through the ventral telencephalon (VT) and the preoptic area (POA). cGnRH-II-ir cell bodies are located in the midbrain tegmentum (MT). sGnRH but not cGnRH-II is detected in the pituitary. sGnRH peptide levels and sGnRH mRNA levels in the VT and the POA increased during gonadal maturation. sGnRH neurons are derived from the olfactory epithelium and migrate into the brain. In barfin flounder, sGnRH-ir, cGnRH-II-ir, and sbGnRH-ir cell bodies are located in the olfactory bulbs and the terminal nerve ganglion (TN), the MT, and the POA, respectively, and these neurons do not migrate in the brain. sbGnRH is detected in the pituitary. sbGnRH mRNA levels in the brain increased during gonadal maturation. Although three GnRH systems exist in the barfin flounder, anatomical distinction between the TN-and the POA-GnRH systems is not clear in masu salmon. Thus, it is suggested that sGnRH neurons in masu salmon play different roles according to the location in the brain. General introductionGonadotropin-releasing hormone (GnRH) is a decapeptide originally isolated from pig and sheep hypothalami as a physiologic regulator of luteinizing hormone (LH) release from the pituitary (Matsuo et al. 1971;Burgus et al. 1972). At present, it is generally accepted that GnRH regulates synthesis and release of pituitary gonadotropin (GTH) (see King and Millar 1992;Sherwood et al. 1993). It has been shown that two or three molecular forms of GnRH exist, even within the same species (Oka 1997;Okuzawa and Kobayashi 1999;Okubo and Nagahama 2008). In addition, GnRH can act as a neuromodulator and has also been implicated in reproductive behavior in many species including teleost fish such as dwarf gourami Colisa lalia (Yamamoto et al. 1997) and goldfish Carassius auratus (Volkoff and Peter 1999).To date, 15 forms of GnRHs have been identified based on their primary structure or complementary DNAs (cDNAs) in vertebrates, as shown in Fig. 1 (Okubo and Nagahama 2008;Kavanaugh et al. 2008). GnRH forms are traditionally named after the species from which they were first identified. In addition to vertebrate species, GnRH was isolated in invertebrates: e.g., in the protochordate Ciona intestinalis (Powell et al. 1996;Adams et al. 2003), octopus Octopus vulgaris (Iwakoshi et al. 2002) and the sea hare Aplysia californica (Zhang et al. 2008).In mammalian, avian, reptilian, and amphibian animals, GnRH is conveyed to the pituitary via the hypothalamo-hypophyseal portal vessels ( Fig. 2A). In mammals, pulsatile release of mammalian GnRH (mGnRH) by hypothalamic neurons stimulates GTH secretion from the pituitary. However, teleost fishes lack the median eminence. Instead, GnRH neurons are found to directly...

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Three GnRH systems in the brain and pituitary of a pleuronectiform fish, the barfin flounder Verasper moseri

Cited by 63 publications

References 29 publications

Antisense for gonadotropin-releasing hormone reduces gonadotropin synthesis and gonadal development in transgenic common carp (Cyprinus carpio)

Antisense for gonadotropin-releasing hormone reduces gonadotropin synthesis and gonadal development in transgenic common carp (Cyprinus carpio)

Brain morphology and immunohistochemical localization of the gonadotropin-releasing hormone in the bluefin tuna, Thunnus thynnus

Reproductive Biology of Salmoniform and Pleuronectiform Fishes with Special Reference to Gonadotropin-Releasing Hormone (GnRH)

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