Abstract:
:To elucidate the mechanisms of the impaired pituitary response to growth hormone-releasing hormone (GHRH) in aged animals on a cellular basis, a reverse hemolytic plaque assay was performed on dispersed pituitary cells from young (8-month-old) and old (26-month-old) male F344 rats. The proportion of growth hormone (GH)-plaque forming somatotropes, i.e., actually functioning somatotropes, was reduced in old rats to 50-60% of that in young rats under both unstimulated and GHRH-stimulated conditions. The response of dispersed cells to GHRH, however, seemed to remain unchanged with age when expressed as a percent increase of plaque-forming cells from the basal value. The mean diameter of plaques, which reflects the average amount of GH secreted from a single cell, was not smaller in old rats under either the unstimulated or stimulated conditions. There was also no difference between the two age groups in the frequency distribution of the plaque size of functioning somatotropes. The stimulation by forskolin, a compound that directly activates membrane-bound adenylate cyclase and consequently provokes the cyclic adenosine-3',5'-monophosphate (cAMP) pathway for GH secretion in somatotropes, produced almost the same results as those by GHRH stimulation. It was concluded, therefore, that the impaired response of the pituitary gland to GHRH could be due mostly to a reduction in the density of functioning somatotropes rather than to impairments in steps of the GHRH-cAMP signal pathway in somatotropes .
journal_name
Neuroendocrinologyjournal_title
Neuroendocrinologyauthors
Shimokawa I,Higami Y,Okimoto T,Ikeda Tdoi
10.1159/000126799subject
Has Abstractpub_date
1994-12-01 00:00:00pages
575-80issue
6eissn
0028-3835issn
1423-0194journal_volume
60pub_type
杂志文章abstract::Normal 4-day cyclic rats were sacrificed at 10 a.m. and 3 p.m. on proestrus or estrus and at 10 a.m. on metestrus. Noradrenaline (NA), dopamine (DA) and tryptophan (T) concentrations varied only slightly. Serotonin (5-HT) concentrations showed characteristic changing patterns in many hypothalamic, limbic and midbrain ...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000122536
更新日期:1976-01-01 00:00:00
abstract::The exact physiological basis of acute growth hormone (GH) suppression by oral glucose is not fully understood. Glucose-mediated increase in hypothalamic somatostatin seems to be the most plausible explanation. Attempts to better understand its underlying mechanisms are compromised by species disparities in the respon...
journal_title:Neuroendocrinology
pub_type: 杂志文章,评审
doi:10.1159/000497214
更新日期:2019-01-01 00:00:00
abstract::Hemicastration of male rats produced rapid changes in plasma testosterone (T) levels both in summer and in winter. However, in winter, after unilateral castration, the duration of T maximum decrease was found to be longer, but the compensatory increase of blood T following its drop was more dramatic as compared to the...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000122791
更新日期:1978-01-01 00:00:00
abstract::Sexual behavior and elevation of gonadal steroids were induced in both male and female New Zealand white rabbits following injection of synthetic beta (1-24) ACTH into the lateral cerebral ventricle. In blood assays collected by cardiac puncture, testosterone, progesterone and corticosterone were all increased above b...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000122441
更新日期:1975-01-01 00:00:00
abstract::Prolactin release from primary cultured pituitary cells was investigated using a dynamic perifusion system. Although epinephrine (1 mumol/l) produced an elevation in the mean value of the prolactin concentration at the onset of the perifusion, the elevation was not statistically significant, and the overall effect of ...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000126424
更新日期:1993-04-01 00:00:00
abstract::There is a great deal of conflicting data regarding the issue of whether androgens influence opiate receptors in the whole male rat brain. Although Hahn and Fishman initially reported that long-term castration produced a large increase in the density of opiate-binding sites, relative to controls, no other independent ...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000124816
更新日期:1987-08-01 00:00:00
abstract::Incubation of cultured goldfish pituitary cells with 10 nM to 1 microM apomorphine (APO), a non-selective dopamine agonist, increased growth hormone (GH) release in a dose-dependent manner. GH release was also stimulated in a dose-dependent manner by 0.1 nM to 1 microM salmon gonadotropin (GTH)-releasing hormone (sGnR...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000125408
更新日期:1990-06-01 00:00:00
abstract::Allopregnanolone is a neuroactive steroid present in the brain, but also measurable in systemic circulation. It exhibits anxiolytic and anticonvulsant effects and is able to produce hyperphagia. Since eating behavior disturbances and increased peripheral basal sympathetic activity have been reported in obese subjects,...
journal_title:Neuroendocrinology
pub_type: 临床试验,杂志文章,随机对照试验
doi:10.1159/000048228
更新日期:2002-02-01 00:00:00
abstract:BACKGROUND/AIMS:The medial amygdala (MeA) responds to olfactory stimuli and alters reproductive physiology. However, the neuronal circuit that relays signals from the MeA to the reproductive axis remains poorly defined. This study aimed to test whether MeA kisspeptin (MeAKiss) neurons in male mice are sensitive to sexu...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000496106
更新日期:2019-01-01 00:00:00
abstract::Multiple unit activity (MUA) was recorded from the adrenocorticotropic area (n. posterior medialis hypothalami, PMH) of unrestrained resting pigeons throughout the 24 h period and compared with plasma corticosterone levels (B). Bilateral electrolytic lesions of the hippocampus suppressed diurnal variations of MUA and ...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000122750
更新日期:1978-01-01 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::Hereditary cases of growth hormone (GH)-secreting tumors have been classified into three clinical entities: the multiple endocrine neoplasia type 1 (MEN1) syndrome, the Carney complex (CNC) and the isolated familial somatotropinomas (IFS). The genomic defects associated with MEN1 are all linked to various mutations of...
journal_title:Neuroendocrinology
pub_type: 杂志文章,评审
doi:10.1159/000095525
更新日期:2006-01-01 00:00:00
abstract::Binding sites for prolactin were localized and quantified in the female rat brain by in vitro autoradiographic analysis with iodine-125-labeled ovine prolactin. Following incubation, labeled prolactin bound preferentially to the median eminence and choroid plexus of the lateral and third ventricles. The addition of ex...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000125182
更新日期:1989-06-01 00:00:00
abstract::The present study examined the effect of estradiol on hypothalamic serotonin-1A (5-HT(1A)) receptor signaling in female rats. We first examined the time-course effects of a single injection of the 5-HT(1A) receptor agonist (+/-)8-OH-DPAT (5, 15 or 30 min prior to decapitation), and dose response of (+)8-OH-DPAT (50, 1...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000080795
更新日期:2004-01-01 00:00:00
abstract::The effects of intracerebroventricularly (i.c.v.) injected interleukin-1 beta (IL-1 beta: 1, 2.5, 10, and 25 ng) were studied on plasma growth hormone (GH) and prolactin (PRL) concentrations in freely moving rats chronically implanted with i.c.v. cannulas and intracardial catheters. Significant changes in PRL secretio...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000126217
更新日期:1992-07-01 00:00:00
abstract::The relationship between the growth hormone/insulin-like growth factor (GH-IGF)-I status and memory performance is studied in 24 elderly males and females, aged 75-85 years. Positron emission tomography (PET) was used to measure differences in regional cerebral blood flow during the performance of a delayed-non-match-...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000084872
更新日期:2005-01-01 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::Chronic exposure to Delta(9)-tetrahydrocannabinol (Delta(9)-THC) increases corticotropin-releasing hormone (CRH) and proopiomelanocortin (POMC) gene expression in the rat hypothalamus. The levels of circulating gonadal steroids concurrently modulate both neuropeptides in male and female rats. However, it remains unkno...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000054685
更新日期:2001-09-01 00:00:00
abstract::Pathologies involving the pituitary stalk (PS) are generally revealed by the presence of diabetes insipidus. The availability of MRI provides a major diagnostic contribution by enabling the visualization of the site of the culprit lesion, especially when it is small. However, when only an enlarged PS is found, the eti...
journal_title:Neuroendocrinology
pub_type: 杂志文章,评审
doi:10.1159/000506641
更新日期:2020-01-01 00:00:00
abstract::Neuronal nitric oxide synthase, e.g. NADPH diaphorase (NADPH-d), catalyzes formation of the free radical, nitric oxide (NO), and occurs within brain structures that have functional significance for energy fuel homeostasis. The following studies examined whether populations of NADPH-d-positive neurons in the hypothalam...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000054417
更新日期:1999-03-01 00:00:00
abstract::An experiment was performed on 21-day-old male rats to determine the combined effects of pinealectomy, constant light and darkness, and intraperitoneal (i.p.) thyrotropin-releasing hormone (TRH) on pituitary and plasma radioimmunoassayable thyrotropin (TSH), serum thyroxine (T4), and pituitary, thyroid and body weight...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000122751
更新日期:1978-01-01 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:BACKGROUND:The chemotherapy for small-cell lung carcinoma (SCLC) has been adopted for advanced extrapulmonary neuroendocrine carcinomas (EP-NECs). The aim of this study was to clarify the efficacy of standard SCLC regimens when used to treat EP-NECs and to compare the outcome with that for SCLC. METHODS:We reviewed th...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000338794
更新日期:2012-01-01 00:00:00
abstract::This study was designed to investigate the effects of penfluridol, a potent neuroleptic calmodulin inhibitor, on basal and secretagogue-stimulated secretion of thyroid-stimulating hormone (TSH), growth hormone (GH), and luteinizing hormone (LH). The drug had no effect on basal TSH or LH release, but decreased GH relea...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000123548
更新日期:1983-09-01 00:00:00
abstract::Dexras1, a newly identified member of the Ras superfamily of proteins, was discovered in AtT-20 corticotrope cells because its expression was induced in response to glucocorticoids (dexamethasone; Dex). As yet, the function of Dexras1 is unknown, but its rapid induction in response to glucocorticoids suggests the poss...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000054691
更新日期:2001-10-01 00:00:00
abstract::When fetal preoptic area (POA) brain grafts that contain gonadotropin-releasing hormone cells are transplanted into the third ventricle of adult female hypogonadal mice, the animals respond with sexual maturation, persistent estrus, and the ability to ovulate reflexively after mating. However, the absence of normal sp...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000124998
更新日期:1988-08-01 00:00:00
abstract::Dopaminergic agonists are effective in vivo in inhibiting lactotrope proliferation and prolactin (PRL)-secreting pituitary tumors. The purpose of the present study was to demonstrate in vitro actions of dopaminergic agents on proliferation and cell shape of rat lactotropes. Anterior pituitary cells cultured with serum...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000054362
更新日期:1998-09-01 00:00:00
abstract::The mu-opioid receptor (OR) is involved in several aspects of female reproductive neuroendocrinology, such as the control of gonadotropin release and the display of lordosis behavior. Even though the neuroendocrine events modulated by mu-ORs are steroid hormone-dependent, few studies have shown how steroid hormones su...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000065953
更新日期:2002-10-01 00:00:00
abstract:INTRODUCTION:Several studies have suggested that diet, especially one enriched in microbiota-fermented fibers or fat, regulates behavior. The underlying mechanisms are currently unknown. We previously reported that certain macronutrients (fermentable fiber and protein) regulate energy homeostasis via the activation of ...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000514289
更新日期:2021-01-11 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