Possible Role of Dexamethasone in Sensitizing the Beta-2-Adrenergic Receptor System in vivo in Calves during Concomitant Treatment with Clenbuterol

Pharmacology ◽  
2004 ◽  
Vol 72 (3) ◽  
pp. 196-204 ◽  
Author(s):  
G. Abraham ◽  
J. Gottschalk ◽  
F. R. Ungemach
Keyword(s):  
Adrenergic Receptor ◽  
Concomitant Treatment ◽  
Receptor System ◽  
Beta 2

Human tissue adrenergic receptors are not predictive of responses to epinephrine in vivo

1989 ◽  
Vol 256 (5) ◽  
pp. E600-E609
Author(s):  
S. B. Liggett ◽  
S. D. Shah ◽  
P. E. Cryer
Keyword(s):  
Skeletal Muscle ◽  
Adenylate Cyclase ◽  
Adrenergic Receptors ◽  
Adrenergic Receptor ◽  
Interindividual Variation ◽  
Mononuclear Leukocytes ◽  
Circulating Cells ◽  
Beta 2 ◽  
Sufficient Magnitude

To test the hypotheses that adrenergic receptor and adenylate cyclase characteristics of easily accessible circulating cells reflect those of relatively inaccessible extravascular catecholamine target tissues in a subtype-specific fashion and that these characteristics predict responses to catecholamines in vivo, we studied 22 normal humans. Adrenergic receptors and their linked adenylate cyclase systems were measured in mononuclear leukocytes (MNL; beta 2), platelets (alpha 2), skeletal muscle membranes (beta 2), and fat cells (B1 and alpha 2) and compared with the responses to stepped, intravenous epinephrine infusions in vivo. MNL beta 2-adrenergic receptor densities (but not antagonist affinities) were correlated (r = 0.627; P less than 0.01) with skeletal muscle beta 2-adrenergic densities. However, other adrenergic receptor characteristics and basal and maximally stimulated adenosine 3',5'-cyclic monophosphate (cAMP) contents of MNL and all adrenergic receptor characteristics and cAMP contents of platelets were unrelated to the corresponding measurements in skeletal muscle and fat. Furthermore, there were no consistent relationships between tissue adrenergic receptor-adenylate cyclase characteristics and the chronotropic, diastolic depressor, lipolytic, ketogenic, glycemic, or glycogenolytic-glycolytic responses to epinephrine in vivo. Thus the data support the hypothesis that adrenergic receptor densities on circulating cells reflect those of extravascular target tissues in a subtype-specific fashion. On the other hand, the data do not support the hypothesis that physiological interindividual variation of adrenergic receptor characteristics is of sufficient magnitude to alter sensitivity to epinephrine in vivo.

Chronically Elevated Endothelin-1 Concentrations Modulate the β-Adrenergic Receptor System In Vitro and In Vivo

2000 ◽  
Vol 36 ◽  
pp. S157-S159
Author(s):  
Bernhard R. Brehm ◽  
Helmut Heinle ◽  
Teut Risler ◽  
Sabine C. Wolf
Keyword(s):  
Adrenergic Receptor ◽  
Receptor System ◽  
Endothelin 1

Genetic Polymorphisms in the Promoter Region of the beta-2 Adrenergic Receptor Are Associated with the Early Response of Acute Lymphoblastic Leukemia to Chemotherapy.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 1959-1959
Author(s):  
Meyling H. Cheok ◽  
Cong Ding ◽  
Wenjian Yang ◽  
Somas Das ◽  
Dario Campana ◽  
...  
Keyword(s):  
Gene Expression ◽  
Acute Lymphoblastic Leukemia ◽  
Adrenergic Receptor ◽  
Lymphoblastic Leukemia ◽  
Receptor Gene ◽  
High Dose ◽  
A Genome ◽  
Adrb2 Gene ◽  
Beta 2

Abstract Acute lymphoblastic leukemia (ALL) in children is a paradigm of disseminated cancer that is curable with chemotherapy, yet current treatment fails to cure about 20% of patients, for reasons that remain unknown. In a genome-wide assessment of in vivo treatment-induced changes in gene expression in ALL cells using the Affymetrix U95A and U133A oligonucleotide microarray, we found that patients who eventually relapsed did not up-regulate expression of the pro-apoptotic beta-2 adrenergic receptor gene (ADRB2) in their ALL cells after initial treatment with methotrexate and mercaptopurine. After treatment we observed a 5-fold lower level of ADRB2 gene expression in leukemia cells of patients who ultimately relapsed. We found a common genetic polymorphism in the ADRB2 promoter that was significantly linked to high-dose methotrexate induced up-regulation in ADRB2 gene expression in ALL cells. Moreover, the ADRB2 promoter haplotype was significantly linked to poor early treatment response in ALL cells from 242 children (i.e., probability of event-free survival at two years, p=0.0275 stratified by risk groups). These findings have revealed a germline polymorphism that is linked to the early antileukemic effects of ALL chemotherapy and provide new insights into genetic determinants of ALL treatment efficacy.

scholarly journals Restoration of a tumorigenic phenotype by beta 2-microglobulin transfection to EL-4 mutant cells.

1992 ◽  
Vol 175 (3) ◽  
pp. 843-846 ◽  
Author(s):  
R Glas ◽  
K Sturmhöfel ◽  
G J Hämmerling ◽  
K Kärre ◽  
H G Ljunggren
Keyword(s):  
Transfected Cells ◽  
Histocompatibility Complex ◽  
Tumorigenic Potential ◽  
Immunological Recognition ◽  
Beta 2 ◽  
Beta 2 Microglobulin ◽  
First Time ◽  
Mutant Cells

It has frequently been suggested that loss of beta 2-microglobulin (beta 2m) in tumor cells may lead to malignant progression due to escape from immunological recognition. Here, we directly tested the role of beta 2m expression in tumorigenicity. A beta 2 m loss mutant (C4.4-25-), selected from the murine lymphoma EL-4, showed a marked reduction in tumorigenicity as compared with EL-4 in normal C57B1/6 (B6) mice. The reduced tumorigenicity was directly related to beta 2 m expression. Transfection of an intact murine beta 2m gene markedly increased the tumorigenic potential. The reduced tumorigenicity of C4.4-25- compared with beta 2m transfected cells was observed also in athymic B6 nu/nu mice, but was abolished in B6 mice depleted of natural killer (NK) 1.1-positive cells. These results show that restoration of beta 2m expression can promote tumorigenicity and demonstrate for the first time that induction of major histocompatibility complex class I expression by transfection can lead to escape from NK cells in vivo.

scholarly journals Actin filament barbed-end capping activity in neutrophil lysates: the role of capping protein-beta 2.

1995 ◽  
Vol 6 (12) ◽  
pp. 1659-1671 ◽  
Author(s):  
M J DiNubile ◽  
L Cassimeris ◽  
M Joyce ◽  
S H Zigmond
Keyword(s):  
High Speed ◽  
Time Course ◽  
Intact Cell ◽  
Capping Protein ◽  
High Affinity ◽  
Beta 2 ◽  
End Capping ◽  
Pointed End

A barbed-end capping activity was found in high speed supernates of neutrophils lysed in submicromolar calcium. In dilute supernate (> or = 100-fold dilution of cytoplasm), this activity accounted for most of the inhibition of barbed-end elongation of pyrenyl-G-actin from spectrin-F-actin seeds. Pointed-end elongation from gelsolin-capped F-actin seeds was not inhibited at comparable concentrations of supernate, thus excluding actin monomer sequestration as a cause of the observed inhibition. Most of the capping activity was due to capping protein-beta 2 (a homologue of cap Z). Thus, while immunoadsorption of > or = 95% of the gelsolin in the supernate did not decrease capping activity, immunoadsorption of capping protein-beta 2 reduced capping activity proportionally to the amount of capping protein-beta 2 adsorbed. Depletion of > 90% of capping protein-beta 2 from the supernate removed 90% of its capping activity. The functional properties of the capping activity were defined. The dissociation constant for binding to barbed ends (determined by steady state and kinetic analyses) was approximately 1-2 nM; the on-rate of capping was between 7 x 10(5) and 5 x 10(6) M-1 s-1; and the off-rate was approximately 2 x 10(-3) s-1. The concentration of capper free in the intact cell (determined by adsorption of supernate with spectrin-actin seeds) was estimated to be approximately 1-2 microM. Thus, there appeared to be enough high affinity capper to cap all the barbed ends in vivo. Nevertheless, immediately after lysis with detergent, neutrophils contained sites that nucleate barbed-end elongation of pyrenyl-G-actin. These barbed ends subsequently become capped with a time course and concentration dependence similar to that of spectrin-F-actin seeds in high speed supernates. These observations suggest that, despite the excess of high affinity capper, some ends either are not capped in vivo or are transiently uncapped upon lysis and dilution.

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