Somatostatin binding to chicken adenohypophysial membranes

Harvey, S.; Attardo, D.; Baidwan, J. S.

doi:10.1677/jme.0.0040213

Cited by 8 publications

(4 citation statements)

References 35 publications

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“…In support of this hypothesis, biochemical studies have shown the presence of SS1-related peptides (including SS1 and S-28) but not SS2 in the chicken hypothalamus (Hasegawa et al, 1984). The existence of somatostatin-immunoreactive fibers has been reported for the median eminence of birds (Mikami, 1986), and it has been demonstrated that, in chicken, SS1 inhibits the secretion of growth hormone (Harvey et al, 1978(Harvey et al, , 1990Perez et al, 1987;Donoghue and Scanes, 1991) and prolactin (Harvey et al, 1978). In human and rat (de Lecea et al, 1996(de Lecea et al, , 1997Fukusumi et al, 1997), as in chicken (this study), only the PSS1 gene is expressed in the hypothalamus.…”

Section: Functional Significancementioning

confidence: 85%

“…X60191). Although numerous studies have been conducted to determine the distribution of somatostatincontaining neurons (Blä hser, 1984;Nicolardi et al, 1988;Geris et al, 2000) and the effect of SS1 on pituitary hormone secretion in the chicken (Harvey et al, 1978(Harvey et al, , 1990Perez et al, 1987;Donoghue and Scanes, 1991), the existence of a somatostatin variant has not yet been described for birds. In the present study, we have characterized the cDNA encoding PSS2 and have compared the expression pattern of the PSS1 and PSS2 genes in the domestic fowl Gallus gallus.…”

Section: Indexing Terms: Srif; Cortistatin; Central Nervous System; Bmentioning

confidence: 99%

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Characterization of the cDNA encoding a somatostatin variant in the chicken brain: Comparison of the distribution of the two somatostatin precursor mRNAs

Trabucchi¹,

Tostivint²,

Lihrmann³

et al. 2003

J of Comparative Neurology

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Although the existence of two somatostatin variants (SS1 and SS2) has now been demonstrated in the brain of mammals, amphibians, and fish, only one isoform of somatostatin (SS1) has been characterized to date in the brain of birds. Here we report cloning of the cDNA encoding a 101-amino-acid protein (PSS2) that encompasses the somatostatin variant [Pro(2)]somatostatin-14 (SS2) at its C-terminus. Sequence analysis indicated that chicken PSS2 is more closely related to fish PSS2 than to mammalian cortistatin precursors. Northern blot analysis showed that the chicken PSS1 gene is expressed in the central nervous system (CNS) and in the pancreas, whereas the PSS2 gene is expressed only in the CNS and not in peripheral organs. In situ hybridization histochemistry revealed that, in the chicken brain, PSS1 mRNA is more widely distributed than PSS2 mRNA. In particular, PSS1 mRNA expression was found in the hippocampus, the hyperstriatum, the preoptic area, the ventricular hypothalamic nuclei, the optic tectum, and several nuclei of the mesencephalon and rhombencephalon. In contrast, the distribution of PSS2 mRNA was restricted to a few regions of the brain, including the paraolfactory lobe, the paleostriatum, and some nuclei of the mesencephalon and rhombencephalon. The fact that the PSS1 and PSS2 genes are differently expressed in the brain and in peripheral organs indicates that, in chicken, the two somatostatin variants likely exert distinct functions. In particular, the observation that PSS1 mRNA, but not PSS2 mRNA, occurs in the preoptic area and in the ventral hypothalamic nuclei suggests that, of the two somatostatin isoforms, only SS1 acts as a hypophysiotropic factor.

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Section: Functional Significancementioning

confidence: 85%

Section: Indexing Terms: Srif; Cortistatin; Central Nervous System; Bmentioning

confidence: 99%

Characterization of the cDNA encoding a somatostatin variant in the chicken brain: Comparison of the distribution of the two somatostatin precursor mRNAs

Trabucchi¹,

Tostivint²,

Lihrmann³

et al. 2003

J of Comparative Neurology

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“…Radioreceptor assay studies indicate that pituitary SRIH receptors are comparable in birds and mammals (Harvey et al 1990, Geris et al 2000, and partial cDNAs for chicken SRIH receptors show a high degree of homology with their mammalian counterparts (Bossis & Porter 2001, Boardman et al 2002. Therefore the synthetic non-peptidyl sstr agonists (Rohrer et al 1998) can be useful to identify the receptor pathway through which SRIH controls pituitary functions in this species, as has been shown recently (Bossis & Porter 2001).…”

Section: Introductionmentioning

confidence: 99%

Identification of somatostatin receptors controlling growth hormone and thyrotropin secretion in the chicken using receptor subtype-specific agonists

Geris

Groef

Rohrer³

et al. 2003

Journal of Endocrinology

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Somatostatin (SRIH) functions as an endocrine mediator in processes such as growth, immune resistance and reproduction. Five SRIH receptors (sstr1-5) have been identified in mammals, where they are expressed in both the brain and peripheral tissues. To study the specific function of each receptor subtype, specific agonists (ag1-5) have been synthesized. The high degree of homology between mammalian and avian SRIH receptors suggests that these agonists might also be used in chickens. In this paper we describe two in vitro protocols (static incubation and perifusion system) to identify the SRIH receptors controlling the secretion of GH and TSH from the chicken pituitary. We found that basal GH or TSH secretion were never affected when SRIH or an agonist (1 µM) were added. SRIH diminished the GH as well as the TSH response to TSH-releasing hormone (TRH; 100 nM) in both systems. Our results have indicated that the SRIH actions at the level of the pituitary are regulated through specific receptor subtypes. In both the static and flow incubations, ag2 lowered the GH response to TRH, whereas stimulated TSH release was diminished by both ag2 and ag5. Ag3 and ag4 tended to increase rather than decrease the responsiveness of both pituitary cell types to TRH in perifusion studies. Our data have indicated that SRIH inhibits chicken pituitary function through sstr2 and sstr5. Only sstr2 seems to be involved in the control of chicken GH release, whereas both sstr2 and sstr5 inhibit induced GH secretion in mammals. The possible stimulatory action of ag3 and ag4 may point towards a species-specific function of sstr3 and sstr4.

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“…Exogenous SRIF, conversely, suppresses in-vivo thyroidal function ) and inhibits basal and stimulated GH secretion (Scanes & Harvey, 1989a). SRIF also inhibits basal and stimulated GH release from avian pituitary glands in vitro (Perez, Malamed & Scanes, 1987), by effects probably mediated by membrane SRIF-binding sites (Harvey, Attardo & Baidwan, 1990).…”

mentioning

confidence: 99%

Homologous and heterologous regulation of somatostatin-binding sites on chicken adenohypophysial membranes

Harvey

Baidwan²,

Attardo³

1990

Journal of Endocrinology

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Binding of 125I-labelled [Tyr1]-somatostatin (125I-[Tyr1]-SRIF) to pituitary caudal lobe membranes was suppressed in immature chickens 1 and 2 h after i.v. administration of unlabelled SRIF at concentrations of 1-100 micrograms/kg. In-vitro preincubation of chicken pituitary glands for 0.5-4.0 h with 0.1 mumol SRIF/l similarly reduced the binding of 125I-[Tyr1]-SRIF to caudal lobe membrane preparations. After a 4-h incubation in 0.1 mmol SRIF/l, the withdrawal of SRIF from the incubation media was accompanied 4 h later by a partial recovery in the binding of 125I-[Tyr1]-SRIF to pituitary membranes. Passive immunoneutralization of endogenous SRIF resulted in a prompt (within 1 h) and sustained (for at least 24 h) suppression of 125I-[Tyr1]-SRIF binding to pituitary membranes. The i.m. administration of cysteamine (300 mg/kg) to 12-week-old birds depleted hypothalamic SRIF stores and decreased the density of 125I-[Tyr1]-SRIF-binding sites in the caudal and cephalic lobes of the chicken pituitary gland. The reduction in SRIF content and in SRIF-binding sites occurred within 1 h of cysteamine administration and was maintained for at least 24 h. In 6-week-old birds, cysteamine (300 mg/kg) administration suppressed pituitary binding of 125I-[Tyr1]-SRIF for at least 5 days. Circulating concentrations of GH were markedly decreased 1 and 4 h after cysteamine injection, but not after 24 h.(ABSTRACT TRUNCATED AT 250 WORDS)

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Somatostatin binding to chicken adenohypophysial membranes

Cited by 8 publications

References 35 publications

Characterization of the cDNA encoding a somatostatin variant in the chicken brain: Comparison of the distribution of the two somatostatin precursor mRNAs

Characterization of the cDNA encoding a somatostatin variant in the chicken brain: Comparison of the distribution of the two somatostatin precursor mRNAs

Identification of somatostatin receptors controlling growth hormone and thyrotropin secretion in the chicken using receptor subtype-specific agonists

Homologous and heterologous regulation of somatostatin-binding sites on chicken adenohypophysial membranes

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