Abstract:
:The effects of dopamine (DA) on voltage-dependent Ca2+ currents were investigated in cultured rat lactotroph cells using the patch clamp recording technique. Each recorded cell was identified by the reverse hemolytic plaque assay. In the whole-cell configuration, two types of Ca2+ currents, L and T, were characterized on the basis of their kinetics, voltage sensitivity, and pharmacology. The L component had a threshold of -25 mV, showed little inactivation during a 150-msec voltage step, and was maximal at +10 mV. Cadmium ions (100 microM) significantly reduced its amplitude (75%). The T component was activated at a membrane potential close to -50 mV, was maximal at -10 mV, and showed a voltage-dependent inactivation between -90 and -30 mV. It was quickly inactivated during a maintained depolarization (time constant, 27 ms at -30 mV) and was strongly reduced (80%) by nickel ions (100 microM). Bath application of DA (10 nM) caused a markedly general depression of inward Ca2+ currents, acting differently on the T- and L-type currents. DA application shifted the voltage-dependence of the L-type current activation toward depolarization values (8 mV) without modifying its time- and voltage-dependent inactivation. In contrast, DA enhanced the inactivation of the T-type current by accelerating its time-dependent inactivation (25% decrease in the time constant of inactivation) and by shifting the voltage-dependence of the T-type current inactivation toward hyperpolarizing values (-63 mV in control vs. -77 mV in the presence of DA). These effects of DA were dose-dependent and involved the activation of a D2 receptor type. They were mimicked by bromocriptine application (10 nM), whereas sulpiride (100 nM) blocked the DA-evoked response. The D1 antagonist SCH 23390 was ineffective up to 100 microM. All of these DA-induced modifications in Ca2+ currents were abolished using a GTP-free pipette solution or after pretreatment of cells with pertussis toxin, suggesting that DA can regulate the function of Ca2+ channels through GTP-binding proteins (G-proteins). Our results show that DA acts simultaneously by reducing both voltage-dependent Ca2+ currents on lactotroph cells. Thus, DA reduces the entry of Ca2+ ions across the surface membrane and thereby influences electrical activity and the cytosolic free Ca2+ concentration involved in both basal and evoked PRL release.
journal_name
Endocrinologyjournal_title
Endocrinologyauthors
Lledo PM,Legendre P,Israel JM,Vincent JDdoi
10.1210/endo-127-3-990subject
Has Abstractpub_date
1990-09-01 00:00:00pages
990-1001issue
3eissn
0013-7227issn
1945-7170journal_volume
127pub_type
杂志文章相关文献
ENDOCRINOLOGY文献大全abstract::Although the extent of proptosis in exophthalmic Graves' disease has been measured directly and shown to correlate with serum content of a bioassayable exophthalmus-producing factor (EPS;1), a comparable relationship in an experimental model has not been reported. Progressive exophthalmos, measured from photographs an...
journal_title:Endocrinology
pub_type: 杂志文章
doi:10.1210/endo-96-1-151
更新日期:1975-01-01 00:00:00
abstract::Recent in vitro and in vivo evidence shows that secretion of parathyroid hormone (PTH) and calcitonin (CT) is stimulated by beta-adrenergic agonists and inhibited by beta-adrenergic antagonists. To assess the possible roles of adrenal medullary or adrenergic nerve terminal catecholamines in calcium homeostasis, we hav...
journal_title:Endocrinology
pub_type: 杂志文章
doi:10.1210/endo-107-4-977
更新日期:1980-10-01 00:00:00
abstract::The estrogenic and antiestrogenic actions of the geometric isomers of tamoxifen and 4-hydroxytamoxifen were determined in a PRL synthesis assay using primary cultures of dispersed immature rat pituitary gland cells. 4-Hydroxytamoxifen was 100 times more potent as an antiestrogen than tamoxifen. The cis isomer of tamox...
journal_title:Endocrinology
pub_type: 杂志文章
doi:10.1210/endo-122-4-1449
更新日期:1988-04-01 00:00:00
abstract::The activity of hepatic NADPH cytochrome c reductase, an enzyme important in drug and steroid metabolism, increases rapidly during the perinatal period in rats. However, the regulation of this increase is not well understood. To investigate the role of hormones in the development of NADPH cytochrome c reductase activi...
journal_title:Endocrinology
pub_type: 杂志文章
doi:10.1210/endo-110-6-2145
更新日期:1982-06-01 00:00:00
abstract::Glucocorticoids and nonsteroidal antiinflammatory drugs (NSAIDs) are widely used for the treatment of inflammatory and immune diseases. Nitric oxide (NO) has a diversity of physiological functions, but its excess production has been implicated in the inflammatory process. The present study was designed to elucidate th...
journal_title:Endocrinology
pub_type: 杂志文章
doi:10.1210/endo.140.5.6718
更新日期:1999-05-01 00:00:00
abstract::To further characterize the effect of TSH administration on thyroid iodothyronine monodeiodinating activity, we have evaluated the in vitro conversion of T4 to T3 (outer ring deiodination) and T3 to 3,3'-diiodothyronine (T2; inner ring deiodination) by mouse thyroid, liver, and kidney homogenates, comparing tissues fr...
journal_title:Endocrinology
pub_type: 杂志文章
doi:10.1210/endo-116-3-901
更新日期:1985-03-01 00:00:00
abstract::Specific polyclonal antisera to the rat estrogen receptor (rER) were developed using a synthetic peptide as the antigen. The peptide corresponds to amino acids 270-284 deduced from the cloned rER cDNA and has no homology to other steroid hormone receptors. Antipeptide antisera raised in rabbits specifically recognize ...
journal_title:Endocrinology
pub_type: 杂志文章
doi:10.1210/endo-127-3-1028
更新日期:1990-09-01 00:00:00
abstract::The actions of IGFs are regulated at various levels. One mechanism involves binding to IGF-binding protein-3 (IGFBP-3) for transport, thus governing bioavailability. IGFBP3 transcription is modulated by many hormones and agents that stimulate or inhibit growth. We have previously shown in pediatric and adult cohorts a...
journal_title:Endocrinology
pub_type: 杂志文章
doi:10.1210/en.2006-1729
更新日期:2007-12-01 00:00:00
abstract::Androgens and estrogens play major roles in cell differentiation, cell growth, and peptide secretion in steroid target tissues. In addition to the binding of these hormones to their receptors, formation and metabolism are important in the action of steroids. Metabolism of the potent steroid hormones includes glucuroni...
journal_title:Endocrinology
pub_type: 杂志文章
doi:10.1210/endo.142.2.7958
更新日期:2001-02-01 00:00:00
abstract::Interleukin-1 (IL-1) greatly induces osteoclast formation and stimulates bone resorption of mouse calvaria in culture. In the presence of soluble IL-6 receptor (sIL-6R), IL-6 similarly induces osteoclast formation, but the potency of IL-6 in inducing bone resorption in organ culture is weaker than that of IL-1. To stu...
journal_title:Endocrinology
pub_type: 杂志文章
doi:10.1210/endo.139.3.5818
更新日期:1998-03-01 00:00:00
abstract::The interaction of alloxan and cyclic AMP on glucose-induced insulin secretion was studied with the use of isolated rat islet perifusion. Simultaneous perifusion with cyclic AMP and alloxan did not protect the islets against the effect of alloxan. However, addition of dibutyryl cyclic AMP to the alloxan solution produ...
journal_title:Endocrinology
pub_type: 杂志文章
doi:10.1210/endo-100-5-1327
更新日期:1977-05-01 00:00:00
abstract::In humans, the incidence and severity of abdominal aortic aneurysms (AAA) are greater in males than in females. Chronic infusion of angiotensin II (AngII) into apolipoprotein E-deficient (apoE(-/-)) mice promotes atherosclerosis and causes the formation of AAAs. Just as human males are more susceptible to developing A...
journal_title:Endocrinology
pub_type: 杂志文章
doi:10.1210/en.2003-1615
更新日期:2004-08-01 00:00:00
abstract::Isolated renal cortical slices were used to study the conversion of 25-hydroxyvitamin D3 to 1,25-dihydroxyvitamin D3 [1,25-(OH)2D3] and 24,25-dihydroxyvitamin D3 [24,25](OH2)D3] by the rat kidney. Production of 1,25-(OH)2D3 and 24,25-(OH)2D3 was linear with time (30-90 min) and tissue weight (40-250 mg). Production of...
journal_title:Endocrinology
pub_type: 杂志文章
doi:10.1210/endo-109-1-218
更新日期:1981-07-01 00:00:00
abstract::We have recently identified gonadotropes as target cells for ATP action via ATP receptors of the P2U subtype. The present studies have used gonadotrope-derived alpha T3-1 cells to examine the possible signaling mechanisms subserving ATP action in gonadotropes. Addition of ATP produced a biphasic intracellular Ca2+ (Ca...
journal_title:Endocrinology
pub_type: 杂志文章
doi:10.1210/endo.137.1.8536620
更新日期:1996-01-01 00:00:00
abstract::The role of adrenergic stimulation in the regulation of mitogen-activated protein kinase (MAPK) in rat pinealocytes was investigated by measuring phosphorylated MAPK using Western blot analysis and a MAPK enzymatic assay. Stimulation with the endogenous neurotransmitter, norepinephrine (NE; a mixed alpha- and beta-adr...
journal_title:Endocrinology
pub_type: 杂志文章
doi:10.1210/endo.141.12.7856
更新日期:2000-12-01 00:00:00
abstract::Prenatal dexamethasone exposure (PDE) induces multiorgan developmental toxicities in offspring. Here we verified the transgenerational inheritance effect of ovarian developmental toxicity by PDE and explored its intrauterine programming mechanism. Pregnant rats subcutaneously received 0.2 mg/kg/d dexamethasone from ge...
journal_title:Endocrinology
pub_type: 杂志文章
doi:10.1210/en.2018-00044
更新日期:2018-03-01 00:00:00
abstract::The in vitro effect of dopamine, haloperidol and pimozide on 32Pi incorporation into phosphatidylinositol, phosphatidylcholine and phosphatidylethanolamine by anterior pituitary glands was studied. Dopamine decreased the incorporation of 32Pi into phosphatidylinositol in a dose-related manner without affecting phospha...
journal_title:Endocrinology
pub_type: 杂志文章
doi:10.1210/endo-111-1-347
更新日期:1982-07-01 00:00:00
abstract::A method has been developed for the purification of rat placental lactogen employing a specific radioreceptor assay (RRA). The method involves precipitation with ammonium sulfate, gel filtration on Sephadex G-100, ion-exchange chromatography on DEAE-cellulose and CM-Sephadex, and preparative isoelectric focusing. The ...
journal_title:Endocrinology
pub_type: 杂志文章
doi:10.1210/endo-97-3-621
更新日期:1975-09-01 00:00:00
abstract::Benign prostatic hyperplasia is a nonmalignant enlargement of the prostate that commonly occurs in older men. We show that liver X receptor (Lxr)-α knockout mice (lxrα(-/-)) develop ventral prostate hypertrophy, correlating with an overaccumulation of secreted proteins in prostatic ducts and an alteration of vesicular...
journal_title:Endocrinology
pub_type: 杂志文章
doi:10.1210/en.2011-1996
更新日期:2012-07-01 00:00:00
abstract::An ovarian thecal/interstitial cell preparation was obtained by enzymatic digestion of immature rat ovaries depleted of granulosa cells. A component in thecal/interstitial cell-conditioned medium inhibited specific binding of [125I]iodo-epidermal growth factor ([125I]EGF) to its cell surface receptor, as determined wi...
journal_title:Endocrinology
pub_type: 杂志文章
doi:10.1210/endo-121-5-1892
更新日期:1987-11-01 00:00:00
abstract::T4-binding globulin (TBG), the principal carrier of thyroid hormone in serum, is a glycoprotein containing 20% carbohydrate. The importance of the carbohydrate moiety has been previously studied by enzymatic deglycosylation, which showed that deglycosylated TBG retains its original immunological an T4-binding properti...
journal_title:Endocrinology
pub_type: 杂志文章
doi:10.1210/endo-118-4-1614
更新日期:1986-04-01 00:00:00
abstract::We have investigated the interaction of estrogen with GnRH on the regulation of LH subunit mRNA in female hypogonadal (hpg) mice receiving constant frequency and amplitude pulsatile GnRH treatment for up to 18 days. The level of cytosolic common alpha mRNA in female hpg mouse pituitaries was 45 +/- 6% of normal female...
journal_title:Endocrinology
pub_type: 杂志文章
doi:10.1210/endo-124-4-1744
更新日期:1989-04-01 00:00:00
abstract::The epidermis has a great potential as a bioreactor to produce proteins with systemic action. However, the consequences of ectopic epidermal protein overexpression need to be carefully addressed to avoid both local and systemic adverse effects. Thus, the long-term effects of leptin on skin physiology have not been stu...
journal_title:Endocrinology
pub_type: 杂志文章
doi:10.1210/en.2005-0156
更新日期:2005-10-01 00:00:00
abstract::In thyroid epithelial cells, TSH via cAMP induces a rounding up of the cells associated with actin stress fiber disruption, expression of differentiation genes and cell cycle progression. Here we have evaluated the role of small G proteins of the Rho family and their impact on the actin cytoskeleton in these different...
journal_title:Endocrinology
pub_type: 杂志文章
doi:10.1210/en.2005-0329
更新日期:2005-12-01 00:00:00
abstract::Although implantation of GH3 pituitary epithelial cells has been shown to reverse thymic aging in rats, the differentiation pattern of T-lymphocytes within the reconstituted thymus glands has not been investigated. Syngeneic GH3 cells were implanted into 22-month-old female (old) Wistar-Furth rats. Eight weeks later, ...
journal_title:Endocrinology
pub_type: 杂志文章
doi:10.1210/endo.130.5.1572290
更新日期:1992-05-01 00:00:00
abstract::Starvation depresses thyroid gland function. In addition, the peripheral turnover of thyroxine (T4) is reduced, in part due to decreased fecal elimination of T4. The present studies were performed to determine if starvation also affects the deiodinative pathway for T4 degradation. Rats were isotopically equilibrated w...
journal_title:Endocrinology
pub_type: 杂志文章
doi:10.1210/endo-96-6-1525
更新日期:1975-06-01 00:00:00
abstract::The calbindins are Ca-binding proteins whose expression is regulated by 1,25-dihydroxyvitamin D3, the active metabolite of vitamin D3. The calbindins are found in high amounts in the proximal intestine (calbindin-D-9k) and the kidney (calbindin-D-28k), and they are thought to play a role in Ca transport by these tissu...
journal_title:Endocrinology
pub_type: 杂志文章
doi:10.1210/endo-125-6-2950
更新日期:1989-12-01 00:00:00
abstract::Synthetic selective thyroid hormone (TH) receptor (TR) modulators (STRM) exhibit beneficial effects on dyslipidemias in animals and humans and reduce obesity, fatty liver, and insulin resistance in preclinical animal models. STRM differ from native TH in preferential binding to the TRβ subtype vs. TRα, increased uptak...
journal_title:Endocrinology
pub_type: 杂志文章
doi:10.1210/en.2011-1325
更新日期:2012-01-01 00:00:00
abstract::We have used in situ hybridization histochemistry to investigate interactions between the thyroid and adrenal axes in the rat. Propylthiouracil (PTU)-induced hypothyroidism caused a significant reduction in CRH gene transcripts in the paraventricular nucleus of male rats, with a concomitant decrease in both POMC gene ...
journal_title:Endocrinology
pub_type: 杂志文章
doi:10.1210/endo.134.3.8119200
更新日期:1994-03-01 00:00:00
abstract::Progesterone, which is normally produced in the endoplasmic reticulum, was found to be rapidly degraded in the cytosolic fraction of the guinea pig adrenal cortex in vitro. Assuming this finding reflects what happens in vivo raises a question as to the source of progesterone for interacting with a nuclear progesterone...
journal_title:Endocrinology
pub_type: 杂志文章
doi:10.1210/endo-127-3-1114
更新日期:1990-09-01 00:00:00