Neuropeptide Y Stimulates Growth Hormone and Gonadotropin Release from the Goldfish Pituitary in vitro

Peng, Chun; Huang, Yaobo; Peter, Richard

doi:10.1159/000125534

Cited by 81 publications

(40 citation statements)

References 21 publications

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“…The maximal GH responses induced by these GH secretagogues, e.g. dopamine (184% of basal) (43), salmon GnRH (150% of basal) (45), TRH (125% of basal) (44), mammalian neuropeptide Y (150% of basal) (46), and common carp GHRH (175% of basal) (47), were lower than that of zebra fish PACAP 38 (1301 Ϯ 174% of basal). These findings suggest that, unlike mammals, PACAP is not only a modulator of pituitary hormone secretion, but may also function as a novel GH-releasing factor in the goldfish.…”

Section: Discussionmentioning

confidence: 99%

Hypophysiotropic Action of Pituitary Adenylate Cyclase-Activating Polypeptide (PACAP) in the Goldfish: Immunohistochemical Demonstration of PACAP in the Pituitary, PACAP Stimulation of Growth Hormone Release from Pituitary Cells, and Molecular Cloning of Pituitary Type I PACAP Receptor*

et al. 1998

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Pituitary adenylate cyclase-activating polypeptide (PACAP) is a member of the glucagon/secretin peptide family, and its molecular structure is highly conserved in vertebrates. In this study, the functional role of PACAP in regulating GH release in the goldfish was investigated. Using immunohistochemical staining, nerve fibers with PACAP immunoreactivity were identified in the vicinity of goldfish somatotrophs, suggesting that this neuropeptide may influence GH release in the goldfish. The direct regulatory action of PACAP on GH secretion was demonstrated in vitro in perifused goldfish pituitary cells. PACAPs (0.01 nM to 1 M) from different species, including ovine PACAP 27 , ovine PACAP 38 , frog PACAP 38 , zebra fish PACAP 27 , and zebra fish PACAP 38 , were all effective in stimulating GH release with ED 50 values of 8.9 Ϯ 3.5, 3.3 Ϯ 1.6, 14.4 Ϯ 3.5, 15.4 Ϯ 4.1, and 1.4 Ϯ 0.2 nM, respectively. Similar concentrations of vasoactive intestinal polypeptide (VIP), a peptide related to PACAP, was not effective in this respect. In addition, the GH-releasing action of ovine PACAP 38 (10 nM) was inhibited by the PACAP antagonist PACAP 6 -38 (10 M), but not by the VIP antagonist [4-Cl-D-Phe 6 ,Leu 17 ]VIP (10 M). The pharmacology of these GH responses is consistent with the mammalian type I PACAP receptors, suggesting that a similar receptor subtype is present in the goldfish pituitary and mediates the GH-releasing action of PACAP. To establish the structural identity of this goldfish PACAP receptor, a complementary DNA (cDNA) clone sharing a high degree of sequence homology with mammalian type I PACAP receptors was isolated from a goldfish pituitary cDNA library. This cDNA was 5.2 kb in size with a 1.4-kb open reading frame and encoded a 465-amino acid protein with the typical structure of a 7-transmembrane domain-containing, G protein-coupled receptor. Functional expression of this cDNA in COS-7 cells revealed that this fish type I PACAP receptor could be activated by ovine PACAP 27 and PACAP 38 to increase cAMP synthesis with ED 50 values of 2.4 Ϯ 0.8 and 4.2 Ϯ 1.2 nM, respectively. Other structurally related peptides, including VIP (100 nM), GH-releasing hormone (100 nM), glucagon (100 nM), secretin (100 nM), gastric inhibitory polypeptide (100 nM), and PTH (100 nM), were not effective in altering cAMP production. Using Northern blot and RT-PCR, messenger RNA transcripts of this PACAP receptor were identified in the brain, heart, and pituitary of the goldfish. These results, taken together, support the hypothesis that PACAP functions as a novel GH-releasing factor in the goldfish through activation of type I PACAP receptors. (Endocrinology 139: [3465][3466][3467][3468][3469][3470][3471][3472][3473][3474][3475][3476][3477][3478][3479] 1998) P ITUITARY adenylate cyclase-activating polypeptide (PACAP) is a member of the secretin/glucagon/vasoactive intestinal polypeptide (VIP) family (1). In mammals, two biologically active forms of PACAP have been purified, namely PACAP 38 (2) and PACAP 27 (3). PACAP 38 is ...

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Section: Discussionmentioning

confidence: 99%

Hypophysiotropic Action of Pituitary Adenylate Cyclase-Activating Polypeptide (PACAP) in the Goldfish: Immunohistochemical Demonstration of PACAP in the Pituitary, PACAP Stimulation of Growth Hormone Release from Pituitary Cells, and Molecular Cloning of Pituitary Type I PACAP Receptor*

et al. 1998

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“…It should be noticed, however, that in the goldfish both type I PACAP receptor and a GHRH receptor are expressed in the pituitary (Chan et al 1998, Wong et al 1998), indicating that not only PACAP but also GHRH may exert some kind of hypophysiotropic activity. In addition, it has previously been shown that, in birds, amphibians and fish, several regulatory neuropeptides such as gonadotropin-releasing hormone (Marchant et al 1989, Lin et al 1993, Melamed et al 1995, neuropeptide Y (Peng et al 1990), thyrotropinreleasing hormone (Harvey et al 1978, GraciaNavarro et al 1991, Trudeau et al 1992, cholecystokinin (Himick et al 1993), bombesin (Himick & Peter 1995 and corticotropin-releasing hormone (Rousseau et al 1999) are involved in the control of somatotrope cell activity.…”

Section: Evolution Of the Regulation Of Gh Secretion By Ghrh And Pacapmentioning

confidence: 99%

Molecular evolution of the growth hormone-releasing hormone/pituitary adenylate cyclase-activating polypeptide gene family. Functional implication in the regulation of growth hormone secretion

Montero-Hadjadje¹,

Yon²,

Kikuyama³

et al. 2000

Journal of Molecular Endocrinology

121

118

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Growth hormone-releasing hormone (GHRH) and pituitary adenylate cyclase-activating polypeptide (PACAP) belong to the same superfamily of regulatory neuropeptides and have both been characterized on the basis of their hypophysiotropic activities. This review describes the molecular evolution of the GHRH/PACAP gene family from urochordates to mammals and presents the hypothesis that the respective roles of GHRH and PACAP in the control of GH secretion are totally inverted in phylogenetically distant groups of vertebrates. In mammals, GHRH and PACAP originate from distinct precursors whereas, in all submammalian taxa investigated so far, including birds, amphibians and fish, a single precursor encompasses a GHRHlike peptide and PACAP. In mammals, GHRHcontaining neurons are confined to the infundibular and dorsomedial nuclei of the hypothalamus while PACAP-producing neurons are widely distributed in hypothalamic and extrahypothalamic areas. In fish, both GHRH-and PACAP-immunoreactive neurons are restricted to the diencephalon and directly innervate the adenohypophysis. In mammals and birds, GHRH plays a predominant role in the control of GH secretion. In amphibians, both GHRH and PACAP are potent stimulators of GH release. In fish, PACAP strongly activates GH release whereas GHRH has little or no effect on GH secretion. The GHRH/PACAP family of peptides thus provides a unique model in which to investigate the structural and functional facets of evolution.

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“…The quantif ication of the hormone response was done as described by Peng et al [29]. Briefly, the average hormone level of the 3 fractions immediate ly preceding each pulse (prepulse mean) was treated as basal, and the hormone values following a GnRH pulse were expressed as a per centage of this prepulse mean.…”

Section: Discussionmentioning

confidence: 99%

“…In goldfish, GH release is under the stimu latory control of multiple hypothalamic factors [1,10,11,29,[33][34][35][36][37], One of these factors, dopamine has been shown to act via D1 type of receptors to stimulate GH release [35,37], Similarly, TRH stimulates GH secretion from the perifused goldfish pituitary fragments in a dosedependent manner [34], When tested, both SKF38393 (dopamine D1 type agonist) and TRH-stimulated GH secretion from the perifused pituitary fragments. Analog L at 2 \iM had no significant effects on GH release induced either by SKF38393 or by TRH.…”

Section: Discussionmentioning

confidence: 99%

Differential Actions of a Mammalian Gonadotropin-Releasing Hormone Antagonist on Gonadotropin-ll and Growth Hormone Release in Goldfish, <i>Carassius auratus</i>

et al. 1994

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In goldifish the two native forms of gonadotropin-releasing hormone (GnRH), salmon GnRH (sGnRH) and chicken GnRH-II (cGnRH-II), stimulate both gonadotropin-II (GTH-II) and growth hormone (GH) release. Modifications of GnRH structure at positions 1, 2, 3, and 6 often result in an antagonist in goldfish, an observation well documented in mammalian studies. In a preliminary study in goldfish, a mammalian GnRH antagonist, [Ac-D(2)Nal¹, 4Cl-D-Phe², D(3)-Pal^3,6, Arg⁵, D-Ala¹⁰]-mGnRH (analog L) weakly stimulated GTH-II release, and strongly inhibited GH release. The objectives of the present study were to study the dose-related actions of analog L on GTH-II and GH release in the goldfish, the specificity of inhibition of native GnRH actions, and to test whether analog L can act directly on goldfish pituitary cells. In a goldfish pituitary fragments perifusion system, analog L at different concentrations, given as 2-min pulses or as 30-min prolonged treatments, stimulated GTH-II and inhibited GH release in a dose-dependent manner. Analog L at 2 µM concentration (45 min) significantly suppressed sGnRH- and cGnRH-II-stimulated GTH-II as well as GH release. Analog L specifically inhibited GnRH-stimulated GH release, without having any significant effects on the GH release induced by either SKF38393, a dopamine Dl receptor agonist, or thyrotropin-releasing hormone. The GTH-II stimulatory and GH-inhibitory actions of analog L were significantly suppressed by a ‘true’ GnRH antagonist (Ac-Δ³-Pro¹, 4FD-Phe², D-Trp^3,6)-mGnRH. Further, analog L stimulated GTH-II release and suppressed GH release from the enzymatically dispersed goldfish pituitary cells, indicating the direct actions of analog L at the pituitary cell level. Analog L also displaced ¹²⁵I-(D-Arg⁶, Pro⁹ NHEt)-sGnRH bound to crude goldfish pituitary membrane preparations in a dose-related manner. In conclusion, contrary to its action as a potent GnRH antagonist in mammals, analog L has GTH-II stimulatory action in goldfish. Analog L by acting via GnRH receptors at the pituitary cell level differentially acts on GTH-II and GH release, suggesting functional differences in the properties of the GnRH receptors on GTH and GH cells. Analog L also specifically inhibits sGnRH and cGnRH-II actions on GTH-II and GH release.

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Neuropeptide Y Stimulates Growth Hormone and Gonadotropin Release from the Goldfish Pituitary in vitro

Cited by 81 publications

References 21 publications

Hypophysiotropic Action of Pituitary Adenylate Cyclase-Activating Polypeptide (PACAP) in the Goldfish: Immunohistochemical Demonstration of PACAP in the Pituitary, PACAP Stimulation of Growth Hormone Release from Pituitary Cells, and Molecular Cloning of Pituitary Type I PACAP Receptor*

Hypophysiotropic Action of Pituitary Adenylate Cyclase-Activating Polypeptide (PACAP) in the Goldfish: Immunohistochemical Demonstration of PACAP in the Pituitary, PACAP Stimulation of Growth Hormone Release from Pituitary Cells, and Molecular Cloning of Pituitary Type I PACAP Receptor*

Molecular evolution of the growth hormone-releasing hormone/pituitary adenylate cyclase-activating polypeptide gene family. Functional implication in the regulation of growth hormone secretion

Differential Actions of a Mammalian Gonadotropin-Releasing Hormone Antagonist on Gonadotropin-ll and Growth Hormone Release in Goldfish, <i>Carassius auratus</i>

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