Abstract:
:The effect of steroids on the two gonadotropin-releasing hormone (GnRH) forms present in the eel (mammalian GnRH, mGnRH and chicken GnRH-II, cGnRH-II), as well as on gonadotropin (GTH), was studied using specific radioimmunoassays. Female silver eels received chronic treatments with various steroids (estradiol, testosterone, androstenedione, 5 alpha-androstane-3 beta, 17 beta-diol). Estradiol or the combination of estradiol and androgens induced increases in brain and pituitary mGnRH levels and pituitary GTH level, whereas androgens given alone had no significant effect. In contrast, androgens or their combination with estradiol reduced brain cGnRH-II levels (this form remaining undetectable in the pituitary), estradiol given alone having no significant effect. This work demonstrates that the two forms of GnRH undergo a differential regulation by steroids, with a positive estrogen-dependent feedback on mGnRH (as well as on GTH) and a negative androgen-dependent feedback on cGnRH-II. These data are in agreement with previous results obtained in experimentally matured female eels (induced by a gonadotropic treatment which stimulates the production of both estrogens and androgens) showing increases in mGnRH and GTH levels, as well as a decrease in cGnRH-II [1]. The positive feedback of steroids on the mGnRH-GTH axis adds credence to the hypothesis according to which mGnRH would be the main form involved in the control of the gonadotropic function. This positive feedback would play an important role, amplifying pubertal stimulation of the gonadotropic axis, in this fish species.
journal_name
Neuroendocrinologyjournal_title
Neuroendocrinologyauthors
Montero M,Le Belle N,King JA,Millar RP,Dufour Sdoi
10.1159/000126876subject
Has Abstractpub_date
1995-05-01 00:00:00pages
525-35issue
5eissn
0028-3835issn
1423-0194journal_volume
61pub_type
杂志文章abstract::The modulatory actions of ovarian steroids on the norepinephrine (NE) induced alterations in luteinizing hormone (LH) secretion were examined in male and female rats. Long-term (4 weeks) castrated male and female rats bearing chronic third-ventricle cannulae were implanted with intra-atrial catheters. Animals were ble...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000124581
更新日期:1986-01-01 00:00:00
abstract:BACKGROUND:Prolactin-raising antipsychotics, risperidone (antidopaminergic activity), may be associated with low bone mass. On the other hand, risperidone may cause an increase in body weight thought to be favorable for bone. OBJECTIVES:(1) To determine bone remodeling parameters and bone mass in patients with schizop...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000329391
更新日期:2011-01-01 00:00:00
abstract::The release of endogenous noradrenaline in the anterior hypothalamus was studied with microdialysis perfusion in freely moving rats that were subjected to immobilization stress. Experiments were carried out in sham-adrenalectomized and adrenalectomized rats that were first given drinking water containing corticosteron...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000126442
更新日期:1993-05-01 00:00:00
abstract:BACKGROUND:Type I gastric carcinoids (TIGCs) are neuroendocrine neoplasms arising from enterochromaffin-like cells in atrophic body gastritis. Data regarding their evolution in prospective series are scarce, thus treatment and follow-up are not codified. Our aim was to evaluate clinical outcome and recurrence in TIGCs ...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000329043
更新日期:2012-01-01 00:00:00
abstract::In order to evaluate the possible participation of the hypothalamic excitatory and inhibitory amino acid neurotransmitter systems in the GnRH release response to GABAergic drugs, hypothalami (preoptic and mediobasal area) of immature (26 days of age) and adult male rats were perifused with GABA-A and -B agonists and a...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000127133
更新日期:1996-10-01 00:00:00
abstract:BACKGROUND:The reviewing and assessment of epidemiological characteristics of neuroendocrine tumours (NETs) remains a challenge. Despite the fact that it is an uncommon family of neoplasms, several worldwide series have revealed an increasing incidence of this rare condition. However, the data are difficult to compare ...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000441897
更新日期:2017-01-01 00:00:00
abstract::We have found thyroxine 5'-deiodinase in rat posterior pituitary. The isozyme pattern was different in intermediate and neural lobes. The former contained only type I enzyme. In the neural lobe, in euthyroidism only type I was found while in hypothyroidism type II was a prominent form. Since type II 5'-deiodinase has ...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000124871
更新日期:1987-12-01 00:00:00
abstract::Corticosteroids regulate gene expression through the activation of mineralocorticoid and glucocorticoid receptors. The hippocampus contains the highest density of mineralocorticoid and glucocorticoid receptors in the central nervous system. The modulation of neuron excitability by corticosteroids in hippocampal subfie...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000054299
更新日期:1998-01-01 00:00:00
abstract::Glucocorticoid hormones have important effects on brain function in the context of acute and chronic stress. Many of these are mediated by the glucocorticoid receptor (GR). GR has transcriptional activity which is highly context-specific and differs between tissues and even between cell types. The outcome of GR-mediat...
journal_title:Neuroendocrinology
pub_type: 杂志文章,评审
doi:10.1159/000499659
更新日期:2019-01-01 00:00:00
abstract::In vitro and in vivo perfusion techniques were used to examine the changes in the release of beta-endorphin, methionine-enkephalin (met-enkephalin), dynorphin and luteinizing hormone releasing hormone (LHRH) in response to the corticotropin releasing factor (CRF) receptor antagonist, alpha-helical CRF9-41. All four pe...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000124967
更新日期:1988-06-01 00:00:00
abstract:BACKGROUND:Manipulating thyroid hormones has been shown to influence learning and memory. Although a large body of literature is available on the effects of thyroid hormone deficiency on learning and memory functions during developmental or adult-onset hypothyroidism, electrophysiological findings are limited. This lim...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000328513
更新日期:2011-01-01 00:00:00
abstract::The arcuate nucleus-median eminence complex (AM) undergoes major structural and functional changes during normal puberty or if exposed to a pulse of estradiol in the prepuberal period. Those changes are expressed by increased synaptogenesis and by a drastic alteration in the feedback control of anterior pituitary glan...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000124775
更新日期:1987-06-01 00:00:00
abstract::This study compares the processing of pro-opiomelanocortin (POMC) at two Lys-Lys cleavage sites, located in the carboxy-terminal domain of the precursor, one site marking the amino terminus of beta-melanocyte-stimulating hormone (beta-MSH) and the other in the carboxy-terminus of beta-endorphin (beta E). These compari...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000126518
更新日期:1993-07-01 00:00:00
abstract::The relationship between the steroid hormone 17 beta-estradiol and the muscarinic cholinergic receptors present in the preoptic area (POA), median hypothalamus and posterior hypothalamus of female rats was examined in vitro at various stages of the estrous cycle. Muscarinic receptors varied in a cyclic manner, specifi...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000124103
更新日期:1985-05-01 00:00:00
abstract::Endocrine pancreatic tumours (EPTs) are uncommon, with a major challenge to alert physicians to their recognition and requirements of treatment. Functioning EPTs cause well-known clinical syndromes of hormone excess. Insulinomas, gastrinomas and glucagonomas are most common; vipomas and somatostatinomas are rare. EPTs...
journal_title:Neuroendocrinology
pub_type: 杂志文章,评审
doi:10.1159/000080744
更新日期:2004-01-01 00:00:00
abstract::We determined the effect of 17 beta-estradiol (E2) on synthesis and release of luteinizing hormone (LH) induced by drugs which activate intracellular signal transduction mechanisms in rat anterior pituitary cells. Cells were pretreated with E2 (6 x 10(-10) M) or diluent for 24 h, then washed and incubated for 4 h with...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000125405
更新日期:1990-06-01 00:00:00
abstract::To examine the role of excitatory amino acid neurotransmitters in the regulation of LH and FSH secretion in ovariectomized (ovx) adult rats treated with estradiol and progesterone, we measured the release rates of the excitatory amino acid neurotransmitters, glutamate and aspartate, as well as the neurally inactive am...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000126673
更新日期:1994-04-01 00:00:00
abstract::Pregnancy and parturition are associated with opioid-mediated elevations in maternal pain thresholds. This analgesia is subserved by a spinal cord dynorphin/kappa-opiate receptor system. During gestation, elevated pain thresholds are paralleled by a significant increase in the content of dynorphin (1-17 and 1-8) in th...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000126555
更新日期:1993-09-01 00:00:00
abstract::The effect of pinealectomy or immunization against melatonin (Mel) and N-acetylserotonin (NAS) on plasma prolactin (Prl) levels was studied in rats following pineal stimulation induced by blinding or exposure to short photoperiods (1 h light and 23 h darkness daily). Blinding alone or together with pinealectomy or imm...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000122650
更新日期:1977-01-01 00:00:00
abstract::The growth hormone secretagogue receptor subtype 1a (GHSR-1a) is involved in biological actions of ghrelin by triggering intracellular second messengers coupled to heterotrimeric G-protein complex involving Galpha(q/11). Adenosine is a partial agonist of the GHSR-1a, binding to a binding pocket distinct from the one d...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000076042
更新日期:2004-01-01 00:00:00
abstract::The anterior pituitary is permanently regulated by processes of apoptosis and proliferation in order to maintain tissue homeostasis. Several factors have been implicated in this regulation and lately, prolactin (PRL) has been included into that list. However, since PRL is secreted by anterior pituitary lactotropes, th...
journal_title:Neuroendocrinology
pub_type: 杂志文章,评审
doi:10.1159/000354701
更新日期:2013-01-01 00:00:00
abstract::After in vivo treatment, progesterone initially decreases tyrosine hydroxylase (TH) activity in the TIDA neurons, but subsequently increases TH activity with prolonged treatment. In order to explore the cellular mechanism for progesterone's effect, this study examined the acute inhibitory action of progesterone on TH ...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000057336
更新日期:2002-05-01 00:00:00
abstract:BACKGROUND/AIMS:Plasma chromogranin A (CgA) is the most widely used biochemical biomarker in the diagnostic workup and follow-up of gastroenteropancreatic neuroendo- crine neoplasms (GEP-NENs). Herein, we assessed the clinical utility of CgA in diagnosing and monitoring a large series of GEP-NENs. PATIENTS AND METHODS...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000369818
更新日期:2014-01-01 00:00:00
abstract::The incidence of obesity is rapidly escalating and has reached epidemic proportions. In all species, including rodents, humans, and sheep, there is large variation in the degree of weight gain across individuals in response to an obesogenic environment. This individual variation is, at least in part, determined by inn...
journal_title:Neuroendocrinology
pub_type: 杂志文章,评审
doi:10.1159/000455232
更新日期:2017-01-01 00:00:00
abstract::Unlike rats, but similar to primates, guinea pigs exhibit prolonged function of the corpus luteum and elevated progesterone secretion after ovulation. The gonadotropins, estrogen (E) and progesterone (P) have been examined throughout the guinea pig estrous cycle. However, neither prolactin secretion nor its regulation...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000126897
更新日期:1995-06-01 00:00:00
abstract::Gastroenteropancreatic (GEP) neuroendocrine neoplasms (NEN) are a rare, heterogeneous group of tumors that originate from the endocrine system of the gastrointestinal tract and pancreas. GEP-NEN are subdivided according to their differentiation into well differentiated gastroenteropancreatic neuroendocrine tumors (NET...
journal_title:Neuroendocrinology
pub_type: 杂志文章,评审
doi:10.1159/000509864
更新日期:2020-07-02 00:00:00
abstract::In previous studies we demonstrated that insulin-like growth factor I (IGF-I) induces pituitary vasoactive intestinal peptide (VIP) gene expression and secretion, and that IGF-I-induced prolactin (PRL) release is mediated by VIP. In this study, we investigate the mitotropic action of IGF-I and VIP on pituitary lactotr...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000070900
更新日期:2003-05-01 00:00:00
abstract::To further investigate the role of serotonin in human prolactin (Prl) secretion, serotonin antagonists have been administered to healthy volunteers in basal conditions and after pretreatment with the selective blocker of dopamine receptors, pimozide (Pim). Highly significant falls (p less than 0.001) in serum Prl were...
journal_title:Neuroendocrinology
pub_type: 临床试验,杂志文章
doi:10.1159/000122753
更新日期:1978-01-01 00:00:00
abstract::To determine the possible physiological role of endogenous growth hormone-releasing factor (GRF) in the neuronal content and release of cerebral somatostatin (SS), we studied the effect of endogenous GRF blockade on the immunoreactive SS (IR-SS) content of cells and media in fetal rat cerebral cortical and hypothalami...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000126118
更新日期:1992-02-01 00:00:00
abstract::In rats anesthetized with sodium pentobarbital, adrenal venous blood samples were collected and analyzed for epinephrine and norepinephrine by the fluorometric method. Stimulation of the inferior fovea or adjacent areas resulted in a significant increase in epinephrine secretion. Stimulation of some other areas of the...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000122949
更新日期:1979-01-01 00:00:00