Abstract:
:We have used excitatory amino acids as tools to elucidate changes in hypothalamic function associated with lactation, focusing on the regulation of luteinizing hormone (LH) and prolactin secretion. In these studies, we have compared the responsiveness to NMA (N-methyl-D,L-aspartate), an agonist for the N-methyl-D-aspartate (NMDA) receptor, with that of kainate, an agonist for another type of glutamate receptor, the kainate receptor. To address the issue of the permeability of the blood-brain barrier to either NMA or kainate, systemic and central administration of the drugs were compared. Four injections of either drug were administered at 10-min intervals to cycling or lactating rats suckling 8 pups. All of these treatment significantly stimulated LH secretion in cycling rats. However, neither systemic injections of NMA (40 mg/kg) or kainate (2.5-3.5 mg/kg), nor third-ventricular administration of NMA (2 micrograms/2 microliters) or kainate (0.2-0.3 micrograms/2 microliters) stimulated LH secretion during lactation. In contrast, LH responses to NMA were observed in lactating animals suckling 2 pups. These data demonstrate that the intensity of the suckling stimulus determines the degree of gonadotropin-releasing hormone (GnRH) neuronal inhibition during lactation. Recovery of the LH response to NMA in animals suckling 8 pups was not observed after treatment with RU 486 to block the effects of progesterone. Thus, the elevated levels of progesterone during lactation do not appear to play a role in inhibiting GnRH neuronal responsiveness. Removal of the 8-pup suckling stimulus for 24 h also did not restore the LH response to NMA. However, treatment with RU 486 and removal of the suckling stimulus for 24 h did restore LH responses to NMA, suggesting that progesterone may play a role in prolonging the recovery of GnRH neuronal responsiveness. The prolactin responses to NMA and kainate changed with the reproductive state of the animal and the site of administration. Central injections of either drug stimulated prolactin release in both cycling and lactating animals. In contrast, whereas systemic administration of NMA stimulated prolactin secretion in cycling animals, kainate had no effect. In the lactating animals, systemic administration of either drug inhibited prolactin secretion. Thus, the difference in the prolactin responses to systemic administration of the drugs may not only be due to a difference in the distribution of kainate and NMDA receptors but also to the steady state level of activity of the prolactin-releasing and -inhibiting factors which is determined by the reproductive state of the animal.(ABSTRACT TRUNCATED AT 400 WORDS)
journal_name
Neuroendocrinologyjournal_title
Neuroendocrinologyauthors
Abbud R,Smith MSdoi
10.1159/000126576subject
Has Abstractpub_date
1993-10-01 00:00:00pages
454-64issue
4eissn
0028-3835issn
1423-0194journal_volume
58pub_type
杂志文章abstract::In addition to its traditional role as a circulating vasoactive peptide, vasopressin (VP) has been shown to play significant roles in central cardiovascular processing. The recent description of VP receptors within the subfornical organ (SFO) has suggested this circumventricular organ (CVO) as a potential locus for fe...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000127230
更新日期:1997-08-01 00:00:00
abstract:CONTEXT:Early pubertal luteinizing hormone (LH), and by inference gonadotropin-releasing hormone (GnRH), pulse secretion is marked by high nocturnal but low daytime frequency; however, the underlying mechanisms remain unclear. Plasma concentrations of progesterone, the major regulator of GnRH frequency in women, increa...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000336395
更新日期:2012-01-01 00:00:00
abstract::The secretion of gonadotropins and the role exerted by the endogenous opioid system on luteinizing hormone (LH) secretion were investigated in 6 postmenopausal women affected by idiopathic Parkinson's disease (PD) as well as in 6 age- and weight-matched normal postmenopausal women as controls. The mean plasma follicle...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000125773
更新日期:1991-06-01 00:00:00
abstract::Patients with active acromegaly are frequently insulin resistant, glucose intolerant, and at risk for developing overt type 2 diabetes. At the same time, these patients have a relatively lean phenotype associated with mobilization and oxidation of free fatty acids. These features are reversed by curative surgical remo...
journal_title:Neuroendocrinology
pub_type: 杂志文章,评审
doi:10.1159/000430819
更新日期:2016-01-01 00:00:00
abstract::We measured the concentration of oxytocin and vasopressin in microdissected areas of the hypothalamus and posterior pituitary in weanling and adult female rats. Oxytocin concentration was significantly less in adult rats as compared to weanling rats in the supraoptic nucleus, median eminence, and retrochiasmatic area ...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000123067
更新日期:1980-08-01 00:00:00
abstract::Recent studies have shown that primary hypothyroidism induced in the rat was able to stimulate the biosynthesis of vasoactive intestinal peptide (VIP) in the anterior pituitary (AP). Since the AP VIP is known to stimulate prolactin (PRL) secretion through a paracrine and/or autocrine mechanism, it is interesting to hy...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000126842
更新日期:1995-02-01 00:00:00
abstract::The effect of intravertebral infusion of angiotensin II on cardiac vagal efferent activity was studied in anesthetized mongrel dogs. Unilateral infusion of doses of angiotensin II as low as 5 ng/kg/min inhibited basal vagal tone and also decreased the slope of the relationship between cardiac vagal efferent activity a...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000124120
更新日期:1985-06-01 00:00:00
abstract::The hypothalamic peptide kisspeptin (metastin), the endogenous ligand of the G protein-coupled receptor KISS1R, plays a critical role in controlling GnRH release from hypothalamic GnRH neurons and thereby regulates hypothalamic-pituitary-gonadal functions. Although the therapeutic potential of kisspeptin is attractive...
journal_title:Neuroendocrinology
pub_type: 杂志文章,评审
doi:10.1159/000357809
更新日期:2014-01-01 00:00:00
abstract::In man and other mammals, starvation is accompanied by a severe suppression of luteinizing hormone-releasing hormone (LHRH) and luteinizing-hormone (LH) secretion, which is caused by unknown alterations in hypothalamic functions. Prostaglandin E2 (PGE2), endorphins and testosterone (T) are know to be strongly involved...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000124034
更新日期:1984-12-01 00:00:00
abstract::The effects of ovarian steroids on baseline blood pressure and on changes of mean arterial pressure in response to centrally administered angiotensin II, prostaglandin E1, and prostaglandin E2 were examined. Ovariectomized rats treated with estradiol or progesterone showed no change of resting blood pressures relative...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000123451
更新日期:1983-02-01 00:00:00
abstract::In vivo single-unit extracellular recording was used to assess neuronal membrane sensitivity at the level of the midbrain central gray (MCG) to the iontophoresis of luteinizing hormone releasing hormone (LHRH) and beta-endorphin (beta-END). The percentage of change in firing rate was evaluated to determine the effect ...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000124792
更新日期:1987-06-01 00:00:00
abstract::An in vitro perifusion system was used to investigate immunoreactive beta-endorphin (beta-END-I) release from adult human hypothalami in response to dopamine (DA) and the DA receptor antagonist haloperidol (HAL). Administration of a 1 microM pulse of DA consistently elicited a mean (+/- SE) 88 +/- 9% increase (p less ...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000124725
更新日期:1987-03-01 00:00:00
abstract:INTRODUCTION:Pituitary neuroendocrine tumors (PitNETs), the most abundant of all intracranial tumors, entail severe comorbidities. First-line therapy is transsphenoidal surgery, but subsequent pharmacological therapy is often required. Unfortunately, many patients are/become unresponsive to available drugs (somatostati...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000505923
更新日期:2020-01-01 00:00:00
abstract::Our previous studies on annexin 5, a member of the annexin family of proteins, have shown its expression in the anterior pituitary gland, its preferential distribution in gonadotropes, and its increase after ovariectomy. In the present study, we examined (1) whether annexin 5 is synthesized in gonadotropes, (2) whethe...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000048216
更新日期:2002-01-01 00:00:00
abstract::Knowledge of specific neurotransmitters as well as the pathways and mechanisms regulating appetite in ruminants that continually graze, such as sheep, is incomplete. Although fundamentally agouti-related protein (AGRP) has a similar function across species to increase food intake, the regulation of AGRP may vary acros...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000082735
更新日期:2004-01-01 00:00:00
abstract::Rats bearing transplanted prolactin-secreting tumors are known to have very high prolactin levels in the serum, reduced hypothalamic opiate concentrations, increasing hypothalamic dopamine synthesis and increased hypophyseal portal blood dopamine levels. Further, it has been shown that incubation in 3H-leucine of ante...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000123211
更新日期:1981-08-01 00:00:00
abstract::Vasoactive intestinal peptide (VIP) gene transcripts were demonstrated by RNA blot hybridization using VIP-specific RNA hybridization probes. High levels of expression were observed as early as in 16-day-old embryos. In aging rats, the VIP-mRNA levels were reduced significantly (in the cerebral cortex) as compared to ...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000124886
更新日期:1988-01-01 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::Delta-sleep-inducing peptide (DSIP) colocalizes within gonadotropin-releasing-hormone (GnRH)-containing neurons in adult hypothalamus and could play a role in the regulation of hypothalamic-pituitary axis in adults. To support the possibility that DSIP also participates in fetal neuroendocrine events and to demonstrat...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000126098
更新日期:1992-01-01 00:00:00
abstract:INTRODUCTION:An increasing number of middle-aged men are being screened for low testosterone levels and the number of prescriptions for various forms of testosterone replacement therapy (TRT) has increased dramatically over the last 10 years. However, the safety of TRT has come into question with some studies suggestin...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000504445
更新日期:2020-01-01 00:00:00
abstract::The hypophysial portal vessels and anterior pituitary glands of adult male rats were surgically exposed, cannulated and infused for 1 min with saline, growth hormone-releasing factor (GH-RF), and dbcAMP. After cessation of infusion, anterior pituitary glands were collected at 1, 5, 15, 30 or 60 min for electron micros...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000122421
更新日期:1975-01-01 00:00:00
abstract::The injection of purified alpha-bungarotoxin (alpha-BTX), an antagonist of the muscle nicotinic cholinergic receptors, into the third ventricle (3rd V) of ovariectomized rats decreased the frequency of pulses of luteinizing hormone (LH) but had no significant effect on the amplitude or nadir of LH secretion. Approxima...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000125153
更新日期:1989-05-01 00:00:00
abstract:BACKGROUND:Craniopharyngioma (CP) is a rare tumor in the elderly whose clinical features and prognosis are not well known in this population. AIM:To evaluate the clinicopathological features and therapeutic outcomes of CP diagnosed in the elderly. PATIENTS AND METHODS:A retrospective, multicenter, national study of C...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000512161
更新日期:2020-10-09 00:00:00
abstract::The effect of in vivo corticosterone manipulation on binding sites for the excitatory neurotransmitter glutamate was determined using radioligand binding to rat brain cryostat sections and crude synaptic membranes. 3H-glutamate binding to regions of the dorsal hippocampal formation was significantly decreased in adren...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000125017
更新日期:1988-09-01 00:00:00
abstract::The frequency of pulsatile release of gonadotropin-releasing hormone (GnRH) and luteinizing hormone (LH) is high in the breeding season and low in the nonbreeding season. These alterations in the patterns of GnRH and LH release are due to an interaction of daylength and gonadal steroid negative feedback. A vast amount...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000076631
更新日期:2004-02-01 00:00:00
abstract::Thyroid hormones and nitric oxide/cyclic guanosine monophosphate (NO/cGMP) signaling play a significant role in the structural development of the cerebellum, respectively. In the present study, the possible contribution of neuronal NO synthase (NOS) and cGMP in the thyroid hormone-induced structural changes was invest...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000203644
更新日期:2009-01-01 00:00:00
abstract::Infusion of 2 nmol atrial natriuretic factor (ANF) into the third cerebroventricle of conscious, orchidectomized male rats results in a significant inhibition of prolactin (PRL) secretion. This effect is prevented by prior treatment with the dopamine receptor antagonist, domperidone. Furthermore, domperidone reverses ...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000124922
更新日期:1988-03-01 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::Although previously considered rare, recent epidemiological studies have revealed that the incidence (3.6/100,000) and prevalence (35/100,000) of gastroenteropancreatic neuroendocrine tumors (GEP-NETs) has increased over the past few decades. Despite the progress in the understanding of GEP-NET molecular biology, ther...
journal_title:Neuroendocrinology
pub_type: 杂志文章,评审
doi:10.1159/000362339
更新日期:2014-01-01 00:00:00
abstract::Gastroenteropancreatic (GEP) endocrine tumors are hypervascular tumors able to synthesize and secrete high amounts of VEGF. We aimed to study the regulation of VEGF production in GEP endocrine tumors and to test whether some of the drugs currently used in their treatment, such as somatostatin analogues and mTOR inhibi...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000289569
更新日期:2010-01-01 00:00:00