Abstract:
:In vivo and in vitro methods have been used to compare the effects of opioid receptor blockade on the functional activity of the hypothalamo-pituitary-gonadal axis in adult (200 g) and sexually immature (50 g) male rats. In the adult, a single injection of the mu-receptor antagonist, naloxone (500 micrograms/100 g body weight, s.c.), produced hypersecretions of luteinizing hormone (LH) and testosterone. Maximal serum concentrations of the two hormones were attained within 20 and 60 min respectively. In contrast, neither ICI 174864 (100 micrograms/100 g body weight, s.c.) nor MR2266 (150 micrograms/100 g body weight, s.c.), which block delta- and kappa-receptors respectively, stimulated pituitary-gonadal activity; indeed, like the saline vehicle, both tended to depress the serum LH concentration. The injection procedure was sufficient to activate the hypothalamo-pituitary-adrenal axis and, thus, the vehicle-treated controls exhibited significant increases in the plasma adrenocorticotrophin and serum corticosterone concentrations. These effects were enhanced by naloxone (500 micrograms/100 g body weight, s.c.) and by the kappa-opioid receptor (MR2266, 150 micrograms/100 g body weight, s.c.) but not by the delta-opioid receptor antagonist (ICI 174864, 30-100 micrograms/100 g body weight, s.c.). The increases in serum corticosterone and LH concentration induced by naloxone in adult rats were not apparent in the sexually immature (50 g) animals. To the contrary, in the young rats naloxone (250 and 500 micrograms/100 micrograms body weight, s.c.) attenuated, in a dose-dependent manner, the pronounced hypersecretion of corticosterone induced by the vehicle injection. The higher dose of the antagonist (500 micrograms/100 g body weight, s.c.) also overcame the significant reductions in serum LH evident 20 (p less than 0.05) and 40 (p less than 0.01) min after the saline injection but the lower dose (250 micrograms/100 g body weight, s.c.) was ineffective in this respect. In vitro, hypothalami from both adult and sexually immature rats responded to the addition of naloxone (10(-8)-10(-6) M) to the incubation medium with significant (p less than 0.01) concentration-dependent increases in the release of gonadotrophin-releasing hormone (GnRH). In contrast, ICI 174864 (10(-7)-10(-6) M) and MR2266 (10(-7)-10(-6) M) had little effect on the secretion of the releasing hormone by hypothalami from rats of either group although, at the highest concentration tested, MR2266 (10(-6) M) precipitated a small increase in GnRH release from hypothalami from adult rats.(ABSTRACT TRUNCATED AT 400 WORDS)
journal_name
Neuroendocrinologyjournal_title
Neuroendocrinologyauthors
Leposavic G,Cover PO,Buckingham JCdoi
10.1159/000125777subject
Has Abstractpub_date
1991-06-01 00:00:00pages
579-88issue
6eissn
0028-3835issn
1423-0194journal_volume
53pub_type
杂志文章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::To determine whether the inhibitory effect of clonidine (CLON) on renin secretion is due in part to a direct action on the kidneys or due entirely to an action on the brain, the drug was administered intravenously in a dose of 30 microgram/kg to dogs in which the spinal cord had been transected in the cervical region....
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000122733
更新日期:1978-01-01 00:00:00
abstract::The effect of stress- or lipopolysaccharide (LPS) endotoxin-induced release of ACTH, beta-endorphin (beta-END) and prolactin (PRL) was investigated in two groups of conscious male rats: (1) Rats pretreated with different H3 receptor agonists, which inhibit neuronal histamine (HA) synthesis and release, and (2) rats wi...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000054402
更新日期:1999-01-01 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::Gonadal steroids exert an important regulatory influence upon the biosynthetic and secretory activity of the somatostatin and growth hormone-releasing hormone (GHRH) neurons controlling the release of growth hormone. It is hypothesized that some of these effects occur in an indirect transsynaptic manner through the st...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000064428
更新日期:2002-08-01 00:00:00
abstract::A significant increase of cell multiplication in inoculated ascitic and solid tumors was demonstrated in both DBA/2 and C57BL/6 mice as well as in Wistar rats after radiofrequency lesions in the median hypothalamus (ventromedial and dorsomedial nuclei; part of arcuate nucleus). The following tests were performed: mito...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000124479
更新日期:1986-01-01 00:00:00
abstract::Hypothalamic norepinephrine (NE) and dopamine content was studied in dogs with spontaneous and iatrogenic hypercortisolism and in untreated normal dogs. The concentration of NE in the hypothalamus was subnormal in 4 of 8 dogs with pituitary-dependent hyperadrenocorticism (PDH), whereas long-term administration of cort...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000123158
更新日期:1981-04-01 00:00:00
abstract::An initial study was performed to ascertain the effects of anisomycin, a reversible inhibitor of protein synthesis, on pulsatile luteinizing hormone (LH) release in adult, ovarietomized (OVX) rats. For this experiment, rats OVX 3-4 weeks earlier were fitted with indwelling atrial cannulae. On the next day (approximate...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000125195
更新日期:1989-07-01 00:00:00
abstract::The studies reported in this paper were undertaken to investigate the effect of chronic (10 day) alcohol consumption on female pituitary-gonadal function. The immature female rat model treated with pregnant mare serum gonadotropin (PMSG) was used since it results in a highly reproducible luteinizing hormone (LH) surge...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000124834
更新日期:1987-10-01 00:00:00
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journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000124190
更新日期:1985-10-01 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::Vasopressin and oxytocin modulate memory processes which effects are dissociated from the typical peripheral endocrine effects of these neuropeptides. Recently, vasopressin has been implicated in the regulation of body temperature. In view of this, experiments were designed to determine whether the antipyretic effect ...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000123554
更新日期:1983-10-01 00:00:00
abstract::Grafts of normal mouse preoptic area (POA) tissue into the third ventricle of gonadotrophin-releasing hormone (GnRH)-deficient hypogonadal (hpg) mice resulted in an elevation of pituitary GnRH receptors, an increased synthesis of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) by the pituitary gland, a...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000124762
更新日期:1987-05-01 00:00:00
abstract::Vasopressin-containing neurosecretory cells are partly regulated by GABAergic neurons present both at the hypothalamic and the pituitary level. In the present work, we compared GABA effects on vasopressin release from posterior pituitaries of Sprague-Dawley (SPD), Wistar (W), Wistar-Kyoto (WKY) and spontaneously hyper...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000126585
更新日期:1993-11-01 00:00:00
abstract::The study was designed to determine whether the ability of central oxytocin (OT) to stimulate gonadotropin-releasing hormone (GnRH) on the afternoon of proestrus (PE) in the cycling female rat is mediated at the level of GnRH terminals within the median eminence (ME), or at higher hypothalamic levels where GnRH cell b...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000054678
更新日期:2001-08-01 00:00:00
abstract::Brain angiotensin II (AII) receptors play a role in the regulation of luteinizing hormone release. This action is thought to involve luteinizing hormone-releasing hormone containing neurons in the preoptic-anterior hypothalamic (POAH) area of the brain. Previous studies have demonstrated a discrete locus of AII recept...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000126225
更新日期:1992-08-01 00:00:00
abstract::Physiological brain aging is characterized by important biochemical and structural changes and by the unbalance among the different neurotransmitters and neuromodulators. The study of the circadian organization of neuroendocrine functions may be considered a clinically reliable tool to investigate the changes of the C...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000126869
更新日期:1995-04-01 00:00:00
abstract::The regulation of prolactin secretion by tuberoinfundibular dopamine (DA) neurons appears to be altered in the aged rat: the concentration of prolactin in the serum increases and the activity of the tuberoinfundibular DA neurons decreases. In the young female rat a brief period of stress reduces the tuberoinfundibular...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000124755
更新日期:1987-05-01 00:00:00
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, testos...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000126876
更新日期:1995-05-01 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 purpose of the present study was to evaluate the opioid receptor subtype mediating opioid modulation of growth hormone (GH) secretion during ontogeny. The mu-agonist morphine and the kappa agonist U50,488 caused a stimulation and inhibition of GH secretion, respectively, on postnatal day 10. Studies on postnatal d...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000127077
更新日期:1996-06-01 00:00:00
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journal_title:Neuroendocrinology
pub_type: 杂志文章,评审
doi:10.1159/000107795
更新日期:2007-01-01 00:00:00
abstract::The postnatal development of the luteinizing hormone-releasing hormone (LHRH) system in male and female rats was investigated using light microscopic immunocytochemistry. An identical number of immunoreactive LHRH cells (about 1,300) was observed for males and females throughout development. Two LHRH cell types, based...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000124516
更新日期:1986-01-01 00:00:00
abstract::It is not known where melatonin acts to influence the neuroendocrine axis of seasonally breeding mammals. However, since the pars tuberalis (PT) contains the highest density of melatonin receptors, this adenohypophyseal subdivision is a potential target. Gonadotropes are the only immunocytochemically detectable adenoh...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000127247
更新日期:1997-10-01 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::We have attempted to elucidate the effect of glucose concentrations on the release of thyrotropin-releasing hormone (TRH), a brain neuropeptide possessing glucoregulatory function, from rat hypothalamic slices in vitro. Rat hypothalamic slices were preincubated for 60 min at 37 degrees C in Krebs-Ringer bicarbonate (K...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000125751
更新日期:1991-04-01 00:00:00
abstract::The present study investigated the effects of short-term exposure to constant light, initiated at the time of ovariectomy, on the ability of estradiol (E2) treatment alone or in conjunction with progesterone (P) to induce afternoon surges of LH and prolactin (PRL). Adult Fischer 344 rats, which had been ovariectomized...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000127009
更新日期:1995-09-01 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:OBJECTIVE:The expression of somatostatin receptors (SSTRs) and dopamine receptor 2 (DR2) in neuroendocrine tumors is of clinical importance as somatostatin analogues and dopamine agonists can be used for their localization and/or treatment. The objective of this study is to examine the expression of the five SSTR subty...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000381061
更新日期:2015-01-01 00:00:00
abstract::[125I]-neuropeptide Y receptors were characterized in the rat pituitary gland using quantitative autoradiography. Scatchard analysis of saturation isotherms showed high affinity (Kd 8.5 x 10(-11) M) and single class of binding sites (Bmax 0.22 pmol/mg of protein) in the posterior lobe of the pituitary gland, with no s...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000125608
更新日期:1990-10-01 00:00:00