Abstract:
:Estradiol (E2) and progesterone (P4) interact to influence tuberoinfundibular dopaminergic neuronal activity and contribute to the control of prolactin (PRL) release. This study examined tyrosine hydroxylase mRNA signal levels in the arcuate nucleus of the hypothalamus and tyrosine hydroxylase activity in the stalk-median eminence after 1 week of steroid treatment and related these to circulating PRL levels. Ovariectomized rats were untreated (control) or were implanted with E2, P4 or both E2 and P4 pellets and were sacrificed after 7 days at either 10:00 or 18:00 h. Some E2 + P4-treated rats were injected with either RU 486 or its vehicle at 12-hour intervals for the last 3 of the 7 days of steroid treatment. Tyrosine hydroxylase mRNA signal levels in the arcuate nucleus were decreased by 70% at both 10:00 and 18:00 h in the E2-treated rats compared to control rats. P4 alone had no effect on tyrosine hydroxylase mRNA levels, but reversed the E2-induced decrease so that mRNA levels in the E2 + P4-treated rats were similar to control levels. The progesterone antagonist RU 486 blocked this effect of P4, supporting the observation of decreased mRNA levels in E2-treated rats. Steroid treatment had no effect on tyrosine hydroxylase mRNA levels in the medial zona incerta. Tyrosine hydroxylase activity in the stalk-median eminence was similar at 10:00 and 18:00 h in control rats, and was decreased by 25 and 36% at 10:00 and 18:00 h, respectively, in E2-treated rats. P4 alone had no effect on tyrosine hydroxylase activity, but reversed the E2-induced decrease in enzyme activity to control levels at both 10:00 and 18:00 h. In contrast to the effect of RU 486 on tyrosine hydroxylase mRNA, tyrosine hydroxylase activity in E2 + P4-treated rats was not significantly altered by RU 486 at either 10:00 or 18:00 h. Circulating PRL levels were elevated in the E2-treated and E2 + P4-treated rats. A diurnal PRL rise was evident at 18:00 h in E2-treated rats, but was abolished by concomitant treatment with P4. The diurnal PRL surge was re-established in E2 + P4-treated rats after administration of RU 486, whereas basal circulating PRL levels were not altered by RU 486. These data indicate that P4 antagonizes the profound inhibitory effect or E2 on tyrosine hydroxylase mRNA content in the tuberoinfundibular dopaminergic neurons.(ABSTRACT TRUNCATED AT 400 WORDS)
journal_name
Neuroendocrinologyjournal_title
Neuroendocrinologyauthors
Arbogast LA,Voogt JLdoi
10.1159/000126583subject
Has Abstractpub_date
1993-11-01 00:00:00pages
501-10issue
5eissn
0028-3835issn
1423-0194journal_volume
58pub_type
杂志文章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::alpha-Methyl-p-tyrosine (alpha-MT), a competitive inhibitor of tyrosine hydroxylase, was used to block the synthesis of hypothalamic catecholamines in immature female rats of 14, 16 and 30 days of age and in castrated adults. The administration of alpha-MT (300 mg/kg body weight, free base) induced a significant decay...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000125611
更新日期:1990-10-01 00:00:00
abstract::The effect of estrogen on prolactin (PRL) synthesis at a single-cell level was studied by in situ hybridization and immunohistochemistry. Long-term estrogen treatment increased PRL-containing cells from 10-20% of total cell population to 80-90%, as revealed by immunohistochemistry. PRL mRNA containing cells also incre...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000124493
更新日期:1986-01-01 00:00:00
abstract::Previous reports have shown that dopamine (DA) in the zona incerta (ZI) has a stimulatory effect on gonadotrophin release. We have now investigated the possibility that steroids exert their feedback effects on the release of luteinizing hormone (LH) via catecholamine systems in the ZI. Since the same steroid regimes a...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000125708
更新日期:1991-02-01 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::The ability of dopamine receptor antagonists to stimulate prolactin release in rats with medial basal hypothalamic lesions was investigated. Starting levels of prolactin were elevated to approximately 400 ng/ml in animals in which the tuberoinfundibular dopaminergic neurons were completely destroyed by the lesion. In ...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000123188
更新日期:1981-06-01 00:00:00
abstract::Central or systemic administration of morphine disrupts maternal behavior in steroid-primed, pup-induced virgin and lactating rats. Morphine, the prototypical mu agonist, also interacts with different opioid receptor subtypes. The present study examined the effectiveness of five receptor-selective agonists, in additio...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000125762
更新日期:1991-05-01 00:00:00
abstract::A consistent group of gonadotropin-releasing hormone (GnRH) cell bodies occurs in the ventral hypothalamic tract at the infundibular lip (IL), just below the arcuate nucleus (ARC), at the site of the so-called GnRH 'pulse generator'. Immunocytochemical studies were performed to examine contacts between these GnRH neur...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000124914
更新日期:1988-03-01 00:00:00
abstract::The aim of this study was to verify whether prolonged exposure of cultured rat anterior pituitary cells to high glucose can alter growth hormone (GH) release and responsiveness to secretagogues. Therefore, we cultured anterior pituitary cells obtained from normal male Sprague-Dawley rats in presence of normal (6 mM) o...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000125947
更新日期:1991-11-01 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::The potential involvement of the sympathoadrenal system in stress-induced secretion of peptides from the intermediate lobe of the pituitary gland and the activation of the pituitary-adrenal axis was studied. Male Wistar rats were subjected to control procedures, to sympathectomy by chronic administration (8 weeks) of ...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000124746
更新日期:1987-04-01 00:00:00
abstract::The capability of the anterior pituitary gland to secrete growth hormone (GH) in response to an intravenous injection of growth hormone-releasing factor, hpGRF-44, was evaluated in male rats ranging from 22 days to 24 months of age. The increase in GH concentrations following a submaximal dose of hpGRF-44 (0.5 microgr...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000123594
更新日期:1983-12-01 00:00:00
abstract::Parturition is initiated in sheep by an increase in the activity of the fetal hypothalamus-pituitary-adrenal (HPA) axis. Prostaglandins, known to augment the activity of this endocrine axis, have long been proposed as involved in the initiation of paturition. We have previously demonstrated that endogenously produced ...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000054548
更新日期:2000-05-01 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::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::Studies were undertaken to determine the effects of chronic stimulation of opiate receptors on the negative feedback effects of testosterone (T) on luteinizing hormone (LH) secretion in the male rat. In an initial study, castrated male rats received replacement levels of T (2 ng/ml) or chronic morphine (M) treatment f...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000124049
更新日期:1985-01-01 00:00:00
abstract::We have previously shown that the serotonergic regulation of renin secretion from the kidneys is mediated by a renin-releasing factor (RRF) that is present in both plasma and hypothalamus. The present studies were designed to determine the distribution of RRF in the brain and peripheral tissues and to test whether RRF...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000126170
更新日期:1992-05-01 00:00:00
abstract::Cell-intact patch-clamp recording was used to determine the electrophysiological responses of sheep anterior pituitary gonadotropes to stimulation with gonadotropin-releasing hormone (GnRH). Cells were identified prior to recording by reverse haemolytic plaque assay (RHPA), or using morphological criteria in preparati...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000126605
更新日期:1993-12-01 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::A patch-clamp study was conducted on cultured frog pituitary melanotrophs, in order to investigate the effects of adrenaline on the electrical activity of these cells. In the whole-cell configuration, adrenaline (1 microM) caused hyperpolarization that was accompanied by a fall in membrane input resistance and a block...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000126633
更新日期:1994-01-01 00:00:00
abstract::To clarify the role and site of action of gamma-aminobutyric acid (GABA) in ovine pineal glands, we have investigated the effects of aminooxyacetic acid (AOAA), an inhibitor of GABA transaminase, on endogenous GABA content and beta-adrenoceptor mediated pineal function in Merino sheep. A significant elevation of endog...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000123892
更新日期:1984-03-01 00:00:00
abstract::The role of endogenous corticoids in fever responses caused by recombinant murine interleukin (IL)-1 beta and IL-6 was studied in adult male Wistar rats. Adrenalectomy diminished the development of fever after intracerebroventricular (icv) injection of these ILs and lowered body temperature. Intraperitoneal administra...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000126682
更新日期:1994-04-01 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 coadministration of growth hormone (GH) secretagogues can provide insight into the neuroregulation of GH secretion. The GH response to L-dopa (125, 250 and 500 mg orally for body weights less than 15 kg, between 15 and 30 kg and greater than 30 kg, respectively), arginine (Arg; 0.5 g/kg infused intravenously over ...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000125536
更新日期:1990-07-01 00:00:00
abstract::Chronic hyperprolactinemia in the rat is associated with suppression of plasma gonadotropin concentrations. The reduction of gonadotropins is considered to be due to either an inhibitory effect of prolactin (PRL) on pituitary gonadotropin secretion and/or suppression of hypothalamic gonadotropin-releasing hormone (GnR...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000126355
更新日期:1993-01-01 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::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::Medial parvocellular paraventricular corticotropin-releasing hormone (mPVN CRH) cells are critical in generating hypothalamic-pituitary-adrenal (HPA) axis responses to systemic interleukin-1beta (IL-1beta). However, although it is understood that catecholamine inputs are important in initiating mPVN CRH cell responses...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000054629
更新日期:2001-02-01 00:00:00
abstract::The effect of altering gamma-aminobutyric acid (GABA) activity on growth hormone (GH) secretion of freely moving chronically cannulated male rats was studied. Systemic injection of the GABA agonist muscimol (2 mg/kg i.v.) inhibited the anticipated secretory episode. Increasing brain GABA levels by gamma-acetylenic-GAB...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000124031
更新日期:1984-12-01 00:00:00
abstract::These studies investigated the effect of aging on thyroid hormone regulation of beta-endorphin in rat corpus striatum and hypothalamus. In both brain areas, basal levels of beta-endorphin declined with age. In addition, age modified the response of beta-endorphin to thyroid hormone status. Hypothyroid rats aged 6 mont...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000123141
更新日期:1981-02-01 00:00:00