Abstract:
:It is well established that PRL secretion is under a tonic inhibition exercised by the hypothalamic dopamine (DA). One feature of this regulation is an immediate withdrawal reaction (elevation of PRL release) of mammotropes after disruption of hypothalamic influence. Although plasma PRL rises rapidly, the suckling stimulus does not cause an acute diminution of hypothalamic DA, but, as we have previously demonstrated, it results in an almost immediate (within 10 min) desensitization of mammotropes as indicated by the change in dose response of DA to inhibit PRL release. Our present investigations relate to the phenomenon of this change in responsiveness of PRL cells. This was accomplished by using the reverse hemolytic plaque assay to evaluate the secretory characteristics of individual PRL secretors derived from lactating rats either before or after a 10-min suckling stimulus. To investigate the mechanism of these changes, the binding characteristics of [3H]spiperone on pituitary membranes from nonsuckled and suckled rats have been compared, and the possible involvement of dephosphorylating enzymes was tested by using okadaic acid (OA) in a dose of 2 nM that preferentially and selectively inhibits protein phosphatase-2A (PP2A) activity. We have also determined the activities of PP1 and PP2A in pituitary tissue samples as well as in enzymatically dispersed cells. Mammotropes from nonsuckled rats exhibited a depression of PRL release after both DA and OA treatment and an elevation after withdrawal of DA. This suggests that the secretory response of mammotropes obtained from nonsuckled rats still shows those two responses that are characteristic of the tonic inhibitory regulation. In contrast, superimposition of suckling in vivo or application of OA together with DA pretreatment in cells from nonsuckled rats in vitro resulted in a disappearance of the dissociation-induced elevation of PRL release, indicating an abolishment of the tonic inhibitory action of DA. Evidence is also presented that the PP2A, but not the PP1, activity of the anterior lobe is significantly lower after a 10-min suckling stimulus. Moreover, DA is able to decrease PP2A activity in dispersed pituitary cells obtained from nonsuckled, but not from suckled, animals. In contrast, there were no differences in either the affinity or the number of binding sites between nonsuckled and suckled rats. Taken together, our results suggest that the suckling-induced decrease in PP2A activity plays a role in the uncoupling of D2 receptors on mammotropes from the tonic inhibitory signaling pathway.
journal_name
Endocrinologyjournal_title
Endocrinologyauthors
Murányi A,Gergely P,Fekete MI,Nagy GMdoi
10.1210/endo.139.11.6322subject
Has Abstractpub_date
1998-11-01 00:00:00pages
4590-7issue
11eissn
0013-7227issn
1945-7170journal_volume
139pub_type
杂志文章相关文献
ENDOCRINOLOGY文献大全abstract::Incubation of bovine corpus luteum slices at 37 C with luteinizing hormone showed that 10.0 microng LH/ml caused a maximum rise in tissue cyclic AMP content within 15 min. Slices incubated with 1.0 or 0.1 microng LH/ml showed a much more gradual accumulation of this nucleotide. In the absence of added LH, a marked dec...
journal_title:Endocrinology
pub_type: 杂志文章
doi:10.1210/endo-100-6-1571
更新日期:1977-06-01 00:00:00
abstract::To elucidate the ligand-receptor relationship of the natriuretic peptide system, which comprises at least three endogenous ligands, atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), and C-type natriuretic peptide (CNP), and three receptors, the ANP-A receptor or guanylate cyclase-A (GC-A), the ANP-B r...
journal_title:Endocrinology
pub_type: 杂志文章
doi:10.1210/endo.130.1.1309330
更新日期:1992-01-01 00:00:00
abstract::The development of androgen responsiveness in the submandibular gland of normal and androgen-resistant (Tfm) mice of different ages was studied after varying hormonal treatments. Total esteroproteolytic (tamase) activity of submandibular gland homogenates was used as a marker for androgen action. Newborn mice of all f...
journal_title:Endocrinology
pub_type: 杂志文章
doi:10.1210/endo-96-6-1571
更新日期:1975-06-01 00:00:00
abstract::Implantation of an embryo induces rapid proliferation and differentiation of uterine stromal cells, forming a new structure, the decidua. One salient feature of decidua formation is a marked increase in maternal angiogenesis. Vascular endothelial growth factor (VEGF)-dependent pathways are active in the ovary, uterus,...
journal_title:Endocrinology
pub_type: 杂志文章
doi:10.1210/en.2008-1207
更新日期:2009-08-01 00:00:00
abstract::The purpose of these studies was to determine whether changes in FSH receptors correlated with FSH-induced attenuation of FSH-responsive adenylyl cyclase in immature porcine granulosa cells. Cells were incubated with FSH (1-1000 ng/ml) for up to 24 h, treated with acidified medium (pH 3.5) to remove FSH bound to cells...
journal_title:Endocrinology
pub_type: 杂志文章
doi:10.1210/endo-123-5-2374
更新日期:1988-11-01 00:00:00
abstract::In female mammals, reproduction is sensitive to the availability of metabolic fuels, and food deprivation has been shown to suppress pulsatile LH secretion, attenuate the preovulatory LH surge, and prevent ovulation. It has been suggested that food deprivation impairs fertility by reducing the secretion of GnRH by GnR...
journal_title:Endocrinology
pub_type: 杂志文章
doi:10.1210/endo.131.5.1425420
更新日期:1992-11-01 00:00:00
abstract::Studies on hormone-receptor interactions generally assume that the formation of a hormone-receptor complex is a reversible process. This assumption has been examined directly in three experiments using liver membrane receptor preparations from pregnant rats and ovine PRL (oPRL). In Exp 1, Receptors were preincubated w...
journal_title:Endocrinology
pub_type: 杂志文章
doi:10.1210/endo-106-1-402
更新日期:1980-01-01 00:00:00
abstract::The atrial natriuretic peptide (ANP) gene is expressed in several extraatrial tissues in which ANP may be involved in the regulation of autocrine or paracrine functions. In the ovary, the synthesis of ANP, its binding sites, and a physiological role were found. The ANP system in the oviduct, however, is yet to be defi...
journal_title:Endocrinology
pub_type: 杂志文章
doi:10.1210/endo.138.6.5160
更新日期:1997-06-01 00:00:00
abstract::Proopiomelanocortin (POMC) neurons in the hypothalamus are direct targets of the adipostatic hormone leptin and contribute to energy homeostasis by integrating peripheral and central information. The melanocortin and beta-endorphin neuropeptides are processed from POMC and putatively coreleased at axon terminals. Mela...
journal_title:Endocrinology
pub_type: 杂志文章
doi:10.1210/en.2002-221096
更新日期:2003-05-01 00:00:00
abstract::Rat epididymal fat cells were isolated and incubated with 25 microunits insulin/ml for 15 minutes. Insulin induced a significant shift in the saturated/unsaturated fatty acid ratio of the cerebroside fraction isolated from fat cell ghosts. This change was due to a decrease of saturated fatty acids and an increase of u...
journal_title:Endocrinology
pub_type: 杂志文章
doi:10.1210/endo-108-5-2014
更新日期:1981-05-01 00:00:00
abstract::Luteinizing hormone/chorionic gonadotropin receptor (LHR) expression in the ovary is regulated by a messenger RNA (mRNA) binding protein, which specifically binds to the coding region of LHR mRNA. We have shown that miR-122, a short noncoding RNA, mediates LHR mRNA levels by modulating the expression of LHR mRNA-bindi...
journal_title:Endocrinology
pub_type: 杂志文章
doi:10.1210/en.2017-03270
更新日期:2018-05-01 00:00:00
abstract::In order to investigate the physiological counterpart of the anatomical finding showing that the dorsal motor nucleus of the vagus nerve (DMX) is a source of efferent vagal fibers innervating the pancreas, unilateral electrical stimulation using monopolar electrodes (50 microA, 30 Hz, 0.2 msec) at a glycemia of 150 mg...
journal_title:Endocrinology
pub_type: 杂志文章
doi:10.1210/endo-112-3-904
更新日期:1983-03-01 00:00:00
abstract::The estrogen receptor (ER) mixed agonists tamoxifen and raloxifene have been shown to protect against bone loss in ovariectomized rats. However, the mechanism by which these compounds manifest their activity in bone is unknown. We have used a series of in vitro screens to select for compounds that are mechanistically ...
journal_title:Endocrinology
pub_type: 杂志文章
doi:10.1210/endo.138.9.5358
更新日期:1997-09-01 00:00:00
abstract::To assess a possible regulatory influence of opioids upon anterior pituitary function in the chimpanzee, we evaluated the effects of the specific opiate receptor antagonist naloxone and the agonistic enkephalin analog [D-Ala2, MePhe4,Met(o)-ol]enkephalin (FK 33-824; Sandoz) on serum levels of PRL, cortisol, FSH, and L...
journal_title:Endocrinology
pub_type: 杂志文章
doi:10.1210/endo-112-6-2168
更新日期:1983-06-01 00:00:00
abstract::The involvement of hypothalamic histaminergic neurons in the stress-induced release of peripheral catecholamines was studied in conscious, freely moving male rats. Blood samples were obtained via a catheter in a femoral artery. Intracerebroventricular infusion of histamine (HA; 30 micrograms) increased the plasma conc...
journal_title:Endocrinology
pub_type: 杂志文章
doi:10.1210/endo-126-3-1430
更新日期:1990-03-01 00:00:00
abstract::The presence of multiple monomeric forms has been described for estrogen receptor (ER) in different target tissues. Using [3H]tamoxifen aziridine ([3H]TA) to covalently label ER and sodium dodecyl sulfate-polyacrylamide gel electrophoresis to analyze labeled products, ER forms were investigated in pituitary cytosol an...
journal_title:Endocrinology
pub_type: 杂志文章
doi:10.1210/endo.131.3.1505480
更新日期:1992-09-01 00:00:00
abstract::The electrical responses of rat islet cells maintained in culture with varying levels of glucose were determined. After culture with 2.8 or 4.2 mM glucose, the beta-cells did not respond electrically to 27.8 mM glucose. However, after culture in 5.6 mM glucose, the cells responded to 27.8 mM glucose in short term expe...
journal_title:Endocrinology
pub_type: 杂志文章
doi:10.1210/endo-102-5-1350
更新日期:1978-05-01 00:00:00
abstract::Ovary-specific acidic protein (OSAP) is a novel molecule discovered from a genomic project designed to identify ovary-selective genes in mice. Whereas public databases suggest extraovarian expression of OSAP, its tissue distribution has not yet been well documented. Thus, the expression profile of mouse and human OSAP...
journal_title:Endocrinology
pub_type: 杂志文章
doi:10.1210/en.2008-1584
更新日期:2009-07-01 00:00:00
abstract::Chorionic gonadotropin (CG) is an early embryo-derived signal that is known to support the corpus luteum. An in vivo baboon model was used to study the direct actions of human CG (hCG) on the endometrium, during the periimplantation period. Endometrial gene expression was analyzed using microarrays. The endometrial bi...
journal_title:Endocrinology
pub_type: 杂志文章
doi:10.1210/en.2006-0832
更新日期:2007-02-01 00:00:00
abstract::PTH-related protein (PTHrP), the major mediator of hypercalcemia of malignancy, reduces tubular phosphate (Pi) reabsorption through its PTH-like renotropic actions. Another peptide detected in tumoral cells, transforming growth factor-beta (TGF beta), has been shown to considerably suppress the sodium-dependent Pi tra...
journal_title:Endocrinology
pub_type: 杂志文章
doi:10.1210/endo.133.1.8391420
更新日期:1993-07-01 00:00:00
abstract::The membrane fraction from the ovaries of pseudopregnant rats exhibits specific, high affinity binding of high density lipoproteins (HDL). Previous studies have indicated that HDL binding in this tissue is up-regulated by hCG and may be involved in supplying cholesterol as substrate for steroid hormone production. To ...
journal_title:Endocrinology
pub_type: 杂志文章
doi:10.1210/endo-126-4-2137
更新日期:1990-04-01 00:00:00
abstract::The aim of this study was to determine whether bisphenol A (BPA) has adverse effects on cardiovascular functions in CD-1 mice and define sex-specific modes of BPA action in the heart. Dams and analyzed progeny were maintained on a defined diet containing BPA (0.03, 0.3, 3, 30, or 300 ppm) that resulted in BPA exposure...
journal_title:Endocrinology
pub_type: 杂志文章
doi:10.1210/en.2014-1847
更新日期:2015-03-01 00:00:00
abstract::Tuberoinfundibular peptide is a recently discovered agonist for the PTH receptor-2; the latter has a wide distribution including the external zone of the median eminence of the hypothalamus, suggesting a role in neuroendocrine function. We have investigated the effects of tuberoinfundibular peptide on the hypothalamo-...
journal_title:Endocrinology
pub_type: 杂志文章
doi:10.1210/endo.142.8.8308
更新日期:2001-08-01 00:00:00
abstract::In the present study we used characterized perifusion model for the development of homologous desensitization to GnRH in the pituitary gonadotrope. This system relies on immobilized primary pituitary cultures that are perifused with various pulse patterns and concentrations of GnRH; these patterns and concentrations a...
journal_title:Endocrinology
pub_type: 杂志文章
doi:10.1210/endo.137.5.8612520
更新日期:1996-05-01 00:00:00
abstract::Maternal obesity at conception increases the risk of offspring obesity, thus propagating an intergenerational vicious cycle. Male offspring born to obese dams are hyperresponsive to high fat-diets, gaining greater body weight, fat mass, and additional metabolic sequelae compared to lean controls. In this report, we id...
journal_title:Endocrinology
pub_type: 杂志文章
doi:10.1210/en.2010-1078
更新日期:2011-11-01 00:00:00
abstract::Gonadotropin-regulated testicular RNA helicase (GRTH/Ddx25) is a posttranscriptional regulator of genes that are essential for spermatid elongation and completion of spermatogenesis. It also prevents Leydig cells (LCs) from gonadotropin overstimulation of androgen production. In transgenic (Tg) mice carrying deletions...
journal_title:Endocrinology
pub_type: 杂志文章
doi:10.1210/en.2012-2230
更新日期:2013-06-01 00:00:00
abstract::We have previously demonstrated that interleukin-1 beta (IL-1 beta), a putative intermediary in the ovulatory process, is a potent stimulator of ovarian PG biosynthesis. In this communication, we examine the possibility that this IL-1 effect reflects in part the induction of arachidonic acid mobilization by phospholip...
journal_title:Endocrinology
pub_type: 杂志文章
doi:10.1210/endo.138.1.4826
更新日期:1997-01-01 00:00:00
abstract::Human pituitary prolactin (hPRL) contains a single major component. Upon iodination by a lactoperoxidase procedure approximately 50% of this component remains ulaltered in molecular size and net charge by the criteria of quantitative polyacrylamide gel electrophoresis (PAGE). Aminiotic fluid hPRL contains two componen...
journal_title:Endocrinology
pub_type: 杂志文章
doi:10.1210/endo-97-2-406
更新日期:1975-08-01 00:00:00
abstract::In cultured rat pituitary cells, increases in the cytosolic calcium concentration ([Ca2+]i) and LH release are induced by activation of GnRH receptors as well as by nonreceptor-mediated stimuli. Treatment of pituitary cells with the myosin light chain kinase (MLCK) inhibitor, wortmannin, attenuated GnRH-induced LH rel...
journal_title:Endocrinology
pub_type: 杂志文章
doi:10.1210/endo.138.4.5078
更新日期:1997-04-01 00:00:00
abstract::Altered leptin action has been implicated in the pathophysiology of heart failure in obesity, a hallmark of which is extracellular matrix remodeling. Here, we characterize the direct influence of leptin on matrix metalloproteinase (MMP) activity in primary adult rat cardiac fibroblasts and focus on elucidating the mol...
journal_title:Endocrinology
pub_type: 杂志文章
doi:10.1210/en.2010-1166
更新日期:2011-05-01 00:00:00