Cloning and characterization of a human leptin receptor using a biologically active leptin immunoadhesin

1997 ◽  
Vol 18 (1) ◽  
pp. 77-85 ◽  
Author(s):  
S-M Luoh ◽  
F Di Marco ◽  
N Levin ◽  
M Armanini ◽  
M-H Xie ◽  
...  
Keyword(s):  
Body Weight ◽  
Binding Sites ◽  
Leptin Receptor ◽  
Short Form ◽  
Biologically Active ◽  
Expression Cloning ◽  
Kidney Cells ◽  
Long Form

ABSTRACT Leptin, the product of the ob gene, is a hormone secreted by fat cells which is primarily involved in the regulation of body weight. We have generated a leptin immunoadhesin (leptin-IgG) which was more potent than leptin alone at reducing body weight and food intake when injected into ob/ob mice. This molecule was used to identify high affinity binding sites on human embryonic 293 kidney cells and subsequently to isolate a cDNA encoding the leptin receptor from this cell line by expression cloning. This receptor corresponds to the short form of the recently isolated leptin receptor. Analysis of the expression pattern of the two forms of receptor by Northern blot, in situ hybridization and quantitative PCR showed that the receptor is expressed in most tissues but that the long form is prevalent in the hypothalamus.

STUDIES ON ACTH-BINDING ANTIBODIES: CHARACTERIZATION OF IMMUNOLOGICAL SPECIFICITIES

1969 ◽  
Vol 62 (3) ◽  
pp. 521-536 ◽  
Author(s):  
M. L. Aubert ◽  
J.-P. Felber
Keyword(s):  
Binding Sites ◽  
Competitive Inhibition ◽  
Biologically Active ◽  
Active Part ◽  
Terminal Portion ◽  
Plasma Acth ◽  
Acth Fragments ◽  
Selection Of

ABSTRACT In investigations on the production and the specificity of anti-ACTH antibodies used for radioimmunoassay, differences have been observed between the various antibodies obtained. It was shown by means of competitive inhibition with different ACTH fragments that the binding of the ACTH molecule to its antibody can occur at different sites along the ACTH peptide. By varying the concentrations of the fragments and the conditions of the assays, it was possible to study the properties of each antibody. Thus antibodies which bind the N-terminal portion, or which exclusively bind the biologically active part of the ACTH chain (1–20), are the most suitable for radioimmunoassay. It was found, however, that the production of antiserum was generally more frequent when binding occurred to the C-terminal portion of the ACTH peptide. Should the presence of such fragments in plasma be confirmed, then the use of these antisera could lead to erroneous measurement of biologically inactive ACTH fragments. Thus, this study reveals that a selection of the antibody for specificity might be necessary for its application to the radioimmunoassay of plasma ACTH, and that this selection could be performed with the use of ACTH fragments. An approach to the problem of binding sites between antigen and antibody has been described and the possibility of introducing a radioimmunoassay for plasma ACTH fragments discussed.

Immunohistochemical characterization of localization of long-form leptin receptor (OB-Rb) in neurochemically defined cells in the ovine hypothalamus

2001 ◽  
Vol 920 (1-2) ◽  
pp. 55-64 ◽  
Author(s):  
Javed Iqbal ◽  
Sueli Pompolo ◽  
Takashi Murakami ◽  
Eric Grouzmann ◽  
Takeshi Sakurai ◽  
...  
Keyword(s):  
Leptin Receptor ◽  
Long Form

Hyperleptinemia and reduced TNF-α secretion cause resistance of db/db mice to endotoxin

2003 ◽  
Vol 284 (3) ◽  
pp. R763-R770 ◽  
Author(s):  
Abram M. Madiehe ◽  
Tiffany D. Mitchell ◽  
Ruth B. S. Harris
Keyword(s):  
Rectal Temperature ◽  
Leptin Receptor ◽  
Short Form ◽  
Endotoxic Shock ◽  
Cytokine Receptors ◽  
Leptin Receptors ◽  
Leptin Deficiency ◽  
Tnf Α ◽  
Long Form

Leptin deficiency in ob/ob mice increases susceptibility to endotoxic shock, whereas leptin pretreatment protects them against LPS-induced lethality. Lack of the long-form leptin receptor (Ob-Rb) in db/db mice causes resistance. We tested the effects of LPS in C57BL/6J db3J/db3J (BL/3J) mice, which express only the circulating leptin receptors, compared with C57BL/6J db/db (BL/6J) mice, which express all short-form and circulating isoforms of the leptin receptor. Intraperitoneal injections of LPS significantly decreased rectal temperature and increased leptin, corticosterone, and free TNF-α in fed and fasted BL/3J and BL/6J mice. TNF-α was increased three- and fourfold in BL/3J and BL/6J, respectively. LPS (100 μg) caused 50% mortality of fasted BL/6J mice but caused no mortality in fasted BL/3J mice. Pretreatment of fasted BL/3J mice with 30 μg leptin prevented the drop in rectal temperature, blunted the increase in corticosterone, but had no effect on TNF-α induced by 100 μg LPS. Taken together, these data provide evidence that fasted BL/3J mice are more resistant than BL/6J mice to LPS toxicity, presumably due to the absence of leptin receptors in BL/3J mice. This resistance may be due to high levels of free leptin cross-reacting with other cytokine receptors.

Ontogeny of the long form of leptin receptor gene expression in the porcine ovarian follicles

2013 ◽  
Vol 16 (1) ◽  
pp. 101-105
Author(s):  
N. Smolinska ◽  
T. Kaminski ◽  
G. Siawrys ◽  
J. Przala
Keyword(s):  
Energy Homeostasis ◽  
Leptin Receptor ◽  
Receptor Gene ◽  
Follicular Development ◽  
Ovarian Follicles ◽  
Antral Follicles ◽  
Long Form ◽  
Rb Gene ◽  
Receptor Gene Expression

Abstract Leptin is a polypeptide hormone produced predominantly in adipocytes. It has been found to be implicated in the regulation of satiety and energy homeostasis. A role for leptin in reproduction was later suggested by findings that this hormone may be involved in the regulation of the hypothalamic- pituitary-gonadal axis via endocrine, paracrine and/or autocrine pathways. The objective of the study was to investigate the ontogeny of the long isoform of leptin receptor (OB-Rb) gene in porcine ovarian follicles. The expression of OB-Rb gene was detected in porcine primordial, primary, secondary and antral follicles by in situ hybridization. In summary, our data suggest that leptin might have a direct effect on porcine follicles and plays an important role in the follicular development.

scholarly journals Phenotypic and Morphometric characterization of indigenous chickens at Jhenaigati upazila of Sherpur district in Bangladesh

2015 ◽  
Vol 12 (2) ◽  
pp. 154-169 ◽  
Author(s):  
F Tabassum ◽  
MA Hoque ◽  
F Islam ◽  
CH Ritchil ◽  
MO Faruque ◽  
...  
Keyword(s):  
Body Weight ◽  
Future Research ◽  
Morphometric Traits ◽  
Indigenous Chicken ◽  
Important Indicator ◽  
Indigenous Chickens ◽  
Affect Body Weight ◽  
Morphometric Characterization

The study was conducted at Rangtia, Shalchura and Dudhnoi villages under Jhenigati upazilla of Sherpur district in Bangladesh for phenotypic and morphometric characterization of indigenous chickens. Among three types of indigenous chickens, Non-descript Deshi were prominent (86%), compared to Cap Headed (10%) and Naked Neck (4%) and the overall mean body weight, back length, body circumference and pelvis width were 961.50 ± 17.79 gm, 152.70 ± 1.29 mm, 219.20 ± 1.89 mm and 25.57 ± .62 mm respectively. The prominent colors of plumage, shank, skin, earlobe and eggshell were multiple (24%), white (52%), white (89%), white & red (47%) and white (48%), respectively while 99% chicken’s had single comb. The highest correlation (0.70) was observed between body weight & body circumference followed by (0.36) between body weight & back length and (0.27) between body weight & pelvis width while eggshell color was significantly correlated with body weight (-0.48), body circumference (-0.41) and pelvis width (-0.26). However, comb type was significantly (p<0.05) affected body weight and pelvis width. But bird type had significant (p<0.05) effect on pelvis width only. Present study reveals that variations in some phenotypic characteristics have significant influence on the pelvis width and body weight while a little change in some morphometric traits may affect body weight of indigenous chickens in Bangladesh which may serve as important indicator trait(s) for future research on the conservation and development of indigenous chicken ecotypes in- situ. DOI: http://dx.doi.org/10.3329/sja.v12i2.21927 SAARC J. Agri., 12(2): 154-169 (2014)

Visualization of gene expression of short and long forms of prolactin receptor in rat digestive tissues

1994 ◽  
Vol 266 (5) ◽  
pp. G807-G815 ◽  
Author(s):  
A. Ouhtit ◽  
P. A. Kelly ◽  
G. Morel
Keyword(s):  
Gene Expression ◽  
Gastrointestinal Tract ◽  
Short Form ◽  
Receptor Gene ◽  
Prolactin Receptor ◽  
High Signal ◽  
Long Form ◽  
Receptor Gene Expression ◽  
Receptor Mrnas

Several effects of prolactin have been characterized in various tissues of the gastrointestinal tract. In the present study, the expression of short and long forms of prolactin receptor was explored and quantified in the digestive tract and correlated to the prolactin specific functions. Sections of all digestive tissues were analyzed by in situ hybridization, using 35S-labeled oligoprobes unique to each form of receptor. Macroautoradiogram signals were quantified and expressed in arbitrary units. In rat liver, prolactin receptor mRNAs are expressed to a much greater degree in females than in males. The short-form transcript is significantly expressed to a greater degree in liver, whereas the long form predominates in the pancreas and esophagus. In the remainder of the gastrointestinal tract, there is an equivalent distribution of short- and long-form transcripts. Relatively high signal intensities are seen in the stomach, duodenum, jejunum, ileum, and colon, whereas the rectum is essentially negative. The identification of prolactin receptor gene expression to limited regions should help establish specific functions associated with this hormone in the digestive tissues.

scholarly journals Characterization of a binding protein for leukemia inhibitory factor localized in extracellular matrix

1993 ◽  
Vol 122 (3) ◽  
pp. 713-719 ◽  
Author(s):  
A Mereau ◽  
L Grey ◽  
C Piquet-Pellorce ◽  
JK Heath
Keyword(s):  
Extracellular Matrix ◽  
Binding Sites ◽  
Leukemia Inhibitory Factor ◽  
Protein A ◽  
Biologically Active ◽  
Inhibitory Factor ◽  
Stable Complex ◽  
Culture Dish ◽  
Chemical Cross Linking

Leukemia Inhibitory Factor (LIF) interacts with two classes of high affinity binding sites on rat UMR cells cultured in monolayer. One class of binding sites was found to be localized in the extracellular matrix (ECM) after removal of cells from the culture dish. The interaction of LIF with ECM-localized binding sites is not dependent upon either glycosylation of LIF or the presence of extracellular glycosyaminoglycans. Chemical cross-linking studies demonstrate that LIF interacts with a 200-kD cell-associated protein and a 140-kD ECM-localized protein. A 140-kD protein could also be specifically precipitated from solubilised metabolically radiolabeled UMR ECM by antibodies directed against LIF by virtue of its ability to form a stable complex with unlabeled LIF. In addition, soluble LIF associated with this ECM-localized protein is biologically active in terms of inhibition of ES cell differentiation. The properties of ECM-localized 140-kD species are very similar to those of the secreted form of the LIF receptor suggesting that the ECM localization of LIF and LIF signal transduction may be closely coupled.

Effect of leptin administration versus re-feeding on hypothalamic neuropeptide gene expression in fasted male rats

2004 ◽  
Vol 82 (12) ◽  
pp. 1128-1134 ◽  
Author(s):  
Edward D McAlister ◽  
Dean A Van Vugt
Keyword(s):  
Gene Expression ◽  
Leptin Receptor ◽  
Primary Source ◽  
Male Rats ◽  
In Situ Hybridization Histochemistry ◽  
Reproductive Axis ◽  
Physiological Relevance ◽  
Long Form ◽  
Induced Changes

Adipocytes are the primary source of circulating leptin. Leptin inhibits eating, increases metabolism, and stimulates the reproductive axis. Numerous hypothalamic neuropeptides have been implicated in leptin's behavioral and neuroendocrine effects, including neuropeptide Y (NPY) and cocaine- and amphetamine-regulated transcript (CART). The aim of this study was to investigate the physiological relevance of leptin's signaling of nutritional status by comparing the effects of leptin with the effects of re-feeding on fasting-induced changes in the expression of the long form of the leptin receptor (Ob-Rb), NPY, and CART. Adult male rats were fasted for 48 h and treated with either intra cere broventricular (i.c.v.) or subcutaneous (s.c.) leptin throughout the fast, or fed ad libitum for 24 h after terminating the fast. Expression of NPY, Ob-Rb, and CART mRNA in the arcuate nucleus (ARC) was determined by in situ hybridization histochemistry and compared with vehicle-treated fed or fasted controls. Fasting increased NPY and Ob-Rb expression and decreased CART expression in the ARC. Leptin (regardless of route) and re-feeding were equally effective in normalizing CART mRNA expression. A similar trend was observed with Ob-Rb expression. In contrast, neither re-feeding nor s.c. leptin reversed the increased expression of NPY that was induced by fasting. Only i.c.v. leptin was effective in this regard. Our results indicate leptin and re-feeding are equally effective in normalizing fasting-induced changes in CART and Ob-Rb expression, but less effective in normalizing NPY expression. These results suggest that leptin is the primary nutritional signal regulating CART and Ob-Rb expression in the ARC, and highlight potential differences between CART and NPY neuron sensitivity to leptin signaling.Key words: CART, leptin receptor, NPY, neuropeptide gene expression, fasting, refeeding, hypothalamus.

scholarly journals Direct in vivo demonstration by radioautography of specific binding sites for calcitonin in skeletal and renal tissues of the rat.

1980 ◽  
Vol 85 (3) ◽  
pp. 682-694 ◽  
Author(s):  
H Warshawsky ◽  
D Goltzman ◽  
M F Rouleau ◽  
J J Bergeron
Keyword(s):  
Binding Sites ◽  
Alveolar Bone ◽  
Specific Binding ◽  
Biologically Active ◽  
Target Cells ◽  
Rat Tissues ◽  
Specific Binding Sites ◽  
Calcitonin Receptors

An in vivo binding assay using radioautography was employed to visualize calcitonin receptors in rat tissues. At 2 min after intravenous injection of biologically active 125I-salmon calcitonin, free hormone was separated from bound hormone by intracardiac perfusion with lactated Ringer's followed by fixation with 2.5% glutaraldehyde. Various tissues were removed and processed for light and electron microscope radioautography. These were compared to tissues removed from animals that received identical amounts of labeled hormone with a large excess of unlabeled calcitonin. Among the tissues investigated, kidney and bone demonstrated labeling. In kidney, most silver grains were located over vesicles below the brush border of cells of theproximal convoluted tubules. These grains were still present after simultaneous injection of excess unlabeled hormone and most likely represented binding to sites involved with ingestion and degradation of hormone from the urinary filtrate. In contrast, grains localized to the basal surfaces of distal convoluted tubule cells were significantly reduced in number in control animals and represented sites of saturable, specific hormone binding. In bone, specific binding sites were found only at the periphery of osteoclasts. These labeled cells were located at resorption sites examined in tibia, humerus, and alveolar bone. This demonstration of the localization of 124I-calcitonin in situ provides a new approach for study the interaction of calcium-regulating hormones with their target cells.

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