Abstract:
:His-dTrp-Ala-Trp-dPhe,Lys-NH2(GHRP-6) is a synthetic compound that releases GH in a dose-response and specific manner in several species and that may well be related to an endogenous compound of similar structure. The aim of this study was to investigate the in vivo GH responses to GHRP-6 in pentobarbital anesthetized rats. Specifically and in order to avoid the influence of endogenous GHRH and somatostatin secretion we studied the GH responses to GHRP-6 in animals with surgical ablation of the hypothalamus, confirmed by histological assessment, as well as in hypophysectomyzed-transplanted rats bearing two hypophyses under the renal capsule. Since it has been previously reported that rats pretreated with GHRH (10 micrograms/kg i.p. every 12 h for 15 days) rather than saline-treated rats have greater GH responses to acutely administered GHRH, we compared the self-potentiating effect of chronic GH pretreatment with GHRP-6 (10 micrograms/kg i.p. every 12 h). Furthermore we also studied the influence of estrogens, glucocorticoids, free fatty acids (FFA) and bombesin on somatotroph responsiveness to GHRP-6 in intact rats. We found a greater GH response to GHRP-6 in rats that underwent a surgical ablation of the hypothalamus 36 h prior to the test than in sham-operated rats. A direct stimulatory effect of GHRP-6 on in vivo GH secretion was demonstrated by a clear GH response to GHRP-6 in hypophysectomyzed-transplanted rats. In addition, we found a similar response whether the animals were pretreated with GHRH or GHRP-6 over the previous 2 weeks. Finally, we found that both estrogen- and testosterone-treated rats have greater GH responses to GHRP-6 than untreated rats. On the other hand, chronic dexamethasone administration, acute elevation of circulating FFA levels and bombesin administration markedly inhibited GH responses to GHRP-6. In contrast to the effects exerted on GH responses to GHRP-6 estrogen administration led to a decrease in GH responses to GHRH while dexamethasone did not affect the GH responses to GHRH, highlighting a differential regulation of these hormones on somatotroph responsiveness to these peptides.
journal_name
Neuroendocrinologyjournal_title
Neuroendocrinologyauthors
Mallo F,Alvarez CV,Benitez L,Burguera B,Coya R,Casanueva FF,Dieguez Cdoi
10.1159/000126366subject
Has Abstractpub_date
1993-01-01 00:00:00pages
247-56issue
2eissn
0028-3835issn
1423-0194journal_volume
57pub_type
杂志文章abstract::The expression of the mouse metallothionein-I (mMT) promoter/human growth hormone (hGH) fusion gene in transgenic mice leads to female sterility and major alterations in the function of the hypothalamic-adenohypophyseal system. These alterations include increases in median-eminence norepinephrine turnover and plasma L...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000125743
更新日期:1991-04-01 00:00:00
abstract::The effect of intraventricular and intravenous (i.v.) hypertonic saline on plasma and perfusate arginine vasopressin (AVP) and oxytocin (OT) levels was determined. A push-pull technique was used to sample third ventricular cerebrospinal fluid (CSF) in the conscious unrestrained rat. Intraventricular perfusion of hyper...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000124008
更新日期:1984-11-01 00:00:00
abstract::The sheep exhibits a marked sex difference in the timing of the pubertal increase in luteinizing hormone (LH). Male lambs undergo a reduction in sensitivity to inhibitory steroid feedback, leading to an increase in LH by 10 weeks of age, but females remain hypersensitive until 30 weeks of age. Endogenous opioids suppr...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000126312
更新日期:1992-12-01 00:00:00
abstract::Corticosterone (CORT) can alter several electrophysiological properties in the hippocampus. Few studies have reported the effects of CORT on hippocampal long-term potentiation (LTP). In the CA1 region of the hippocampal slice, we studied the relative increase in population spike (PS) amplitude after inducing tetanus (...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000126717
更新日期:1994-07-01 00:00:00
abstract::TRPM8 is a member of the melastatin-type transient receptor potential ion channel family. Activation by cold or by agonists (menthol, icilin) induces a transient rise in intracellular free calcium concentration ([Ca(2+)](i)). Our previous study demonstrated that Ca(2+)-permeable cation channels play a role in IGF-1-in...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000101693
更新日期:2007-01-01 00:00:00
abstract::There is extensive evidence that serotonin (5-HT) is implicated in the neuroendocrine control regulating the secretion of several anterior pituitary hormones. It has also been reported that the posterior pituitary is necessary for prolactin (PRL) response to 5-HT as well as to suckling, in which 5-HT implication has b...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000054381
更新日期:1998-11-01 00:00:00
abstract::The following fragments of LHRH were administered intraventricularly and tested for their ability to enhance sexual receptivity in ovariectomized, estrogen-primed female rats: LHRH1-6 NH2, Ac-LHRH5-10, des-Tyr5-LHRH and des-Gly10-LHRH. LHRH1-6 NH2 had no effect on sexual behavior compared to saline-infused controls. A...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000123503
更新日期:1983-06-01 00:00:00
abstract:BACKGROUND:The amygdala receives afferent sensory input and processes information related to hydromineral balance. Angiotensin acts on and through the amygdala to stimulate thirst and sodium appetite. In addition, different angiotensins seem to play a role in cognition and learning mechanisms by acting on and through t...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000328128
更新日期:2011-01-01 00:00:00
abstract::Methanol extracts of rat plasma resulted in release of prolactin (PRL) from rat hemipituitaries in vitro with a linear log-dose relationship. This prolactin-releasing factor (PRF)-like activity was not altered in plasma from rats treated with bromocryptine or chlorpromazine despite significant suppression and stimulat...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000122925
更新日期:1979-01-01 00:00:00
abstract::We have previously reported that the somatotropin regulatory peptides, growth hormone-releasing hormone (GRF) and somatostatin (SS) increase feeding when applied centrally in low picomole-range doses. The similarity between the dose-response characteristics and photoperiod sensitivities of these two peptide's feeding ...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000126372
更新日期:1993-01-01 00:00:00
abstract::Histamine (HA) stimulates the release of the pro-opiomelanocortin (POMC)-derived peptides ACTH, beta-endorphin (beta-END), beta-lipotropin and alpha-melanocyte-stimulating hormone, and HA is involved in the mediation of the stress-induced release of these peptides. The effect of HA is indirect and may involve the hypo...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000126258
更新日期:1992-09-01 00:00:00
abstract::Introduction The membrane-associated G protein-coupled estrogen receptor 1 (GPER) mediates the regulation by estradiol on arginine-vasopressin immunoreactivity in the supraoptic and paraventricular hypothalamic nuclei of female rats and is involved in the estrogenic control of hypothalamic regulated functions, such as...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000509583
更新日期:2020-06-22 00:00:00
abstract::The effects of delta 9-tetrahydrocannabinol (THC) on hypothalamic norepinephrine (NE) and dopamine (DA) turnover and hypothalamic serotonin (5-HT), 5-hydroxyindole acetic acid (5-HIAA) and LHRH content preceding and during a progesterone- (P) induced LH and prolactin (PRL) surge were investigated in ovariectomized est...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000123576
更新日期:1983-11-01 00:00:00
abstract::The possibility was investigated that centrally administered rat prolactin (PRL), i.e., intracerebroventricularly (ICV) or intrathecally (IT), may influence mammary contractility in urethane-anesthetized lactating rats. In addition to the monomer (23 kD PRL), the 16- and 7-kD PRL fragments were also tested and their e...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000127006
更新日期:1995-08-01 00:00:00
abstract::Secretion of the growth hormone (GH) in spontaneously hypertensive (SH) male rats has been determined and compared with that of normotensive Wistar-Kyoto (WKY) controls. In a first set of experiments, plasma GH concentration and pituitary GH content were measured in SH rats 30, 60 and 90 days old. 30-day rats showed r...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000125617
更新日期:1990-10-01 00:00:00
abstract::In previous studies we obtained evidence that serotonin release by p-chloroamphetamine (PCA) causes an increase in corticosterone secretion but that this effect is not mediated via the raphe nuclei in the midbrain. In contrast, PCA-induced prolactin secretion was abolished by dorsal raphe lesions. In the present study...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000124205
更新日期:1985-11-01 00:00:00
abstract::The orphanin-FQ/nociceptin (OFQ/N) receptor (previously, ORL1, LC132) has been shown to be coupled to an inwardly rectifying K+ conductance in several neuronal populations. Although OFQ/N receptor mRNA is densely expressed in the supraoptic nucleus (SON), little is known about its coupling to effector system(s). The p...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000054441
更新日期:1999-05-01 00:00:00
abstract::The properties of neuronal-type nicotinic acetylcholine receptors (nAChRs) present on the neuroendocrine cells of the porcine pars intermedia of the pituitary were studied in intact single cell using measurements of the free intracellular Ca2+ concentration ([Ca]i) with the calcium-sensitive dye fura 2. Local applicat...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000126772
更新日期:1994-10-01 00:00:00
abstract::The known occurrence of opiates in the adrenals stimulated us to determine whether Tyr-MIF-1 (Tyr-Pro-Leu-Gly-NH2), an endogenous peptide that can act as an antiopiate, is present in these glands and whether adrenalectomy affects its concentrations in plasma. The presence of Tyr-MIF-1 in the adrenals of the rat was sh...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000126403
更新日期:1993-03-01 00:00:00
abstract::Dopamine D2 receptor (D2R) participation in prolactin regulation is well documented, but the role of D2Rs in the control of other hormones involved in growth, food intake and glucose metabolism has not been extensively studied. The study of D2R knockout mice (Drd2(-/-)) puts forward new insights into the role of the D...
journal_title:Neuroendocrinology
pub_type: 杂志文章,评审
doi:10.1159/000321395
更新日期:2010-01-01 00:00:00
abstract:BACKGROUND/AIMS:Estrogen receptor-alpha (ER alpha) splice variants are important for understanding estrogen effects on the brain and estrogen therapy pitfalls. We addressed the question whether a novel ER alpha splice variant TADDI is expressed at the protein level in the human brain and whether it changes in relation ...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000158573
更新日期:2009-01-01 00:00:00
abstract::The inhibitory effects of pituitary allografts on the prolactin (PRL)-secretory system are presumed to be consequences of the unabated release of PRL by the allografts. In the present studies we used pituitary allografts in the Golden Syrian hamster to address the following questions: (a) Do allografts of adult adenoh...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000127068
更新日期:1996-05-01 00:00:00
abstract::Interactions between the hypothalamic-pituitary-adrenocortical (HPA) system and melatonin secretion have been demonstrated, but only the effects of melatonin on the activity of the HPA system have been studied in man. Alterations of melatonin secretion described as low-melatonin syndrome have been demonstrated in pati...
journal_title:Neuroendocrinology
pub_type: 临床试验,杂志文章,随机对照试验
doi:10.1159/000127186
更新日期:1997-04-01 00:00:00
abstract:BACKGROUND:The outcomes of bariatric surgery are very irregular and mostly unpredictable. The search for variables of predictive value is encouraged to help preventing therapeutic failures. OBJECTIVE:We aimed to confirm the hypothesis that preexisting eating behaviors could predict neuroendocrine and metabolic outcome...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000500687
更新日期:2020-01-01 00:00:00
abstract::In experiment I we studied the capacity of progesterone (P) and two nonsteroidal agents that activate lordosis, but do not bind to the progestin receptor (PR), i.e. luteinizing hormone-releasing hormone (LHRH) and prostaglandin E2 (PGE2) to induce sequential inhibition (SI) in ovariectomized estradiol-primed rats. The...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000126457
更新日期:1993-05-01 00:00:00
abstract::Neonatal rats exhibit a period of diminished pituitary and adrenocortical responses to stress during the first 2 weeks of life. Since thyroid hormones are known to affect brain development, modulation of these responses to stress by alterations in thyroid hormone status have been investigated in hypothyroid (Hypo) and...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000125232
更新日期:1989-09-01 00:00:00
abstract::The role of beta-endorphin in the stimulation of growth hormone secretion elicited by administration of clonidine (Clon), an alpha2-adrenergic agonist, was investigated in awake, freely moving male rats. Animals were infused slowly with either 1 ml of normal rabbit serum (NRS), beta-endorphin antiserum (beta-end-AS) o...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000125263
更新日期:1989-10-01 00:00:00
abstract::Prolactin-releasing (PRF) activity was found in Pitressin (a commercial extract from posterior pituitary for vasopressin). Injection of Pitressin into conscious free-moving rats implanted with a permanent atrial indwelling cannula, produced a transient increase in prolactin concentration in the circulation. In order t...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000123277
更新日期:1982-01-01 00:00:00
abstract::Ghrelin is a 28-amino-acid gastric peptide that potently stimulates growth hormone (GH) secretion in vivo and in vitro. Ghrelin-expressing cells have been found in the oxyntic region of the stomach and in the arcuate nucleus of the hypothalamus. The aim of this work was to investigate the regional distribution and dev...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000068653
更新日期:2003-02-01 00:00:00
abstract::The effects of acute stress exposure upon cholecystokinin (CCK) and substance P (SP) concentrations in discrete hypothalamic regions of the adult male rat brain were studied. Animals were exposed to foot shock stress for periods of 2, 4, 10, 30 or 60 min duration; immediately afterwards they were decapitated; brains w...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000124799
更新日期:1987-06-01 00:00:00