Crude urinary human chorionic gonadotropin contains variant forms of HCG with low sialic acid content that exhibit an increased thyrotropic activity in CHO cells expressing the human TSH receptor

2009 ◽  
Vol 103 (03) ◽  
pp. 168-174 ◽  
Author(s):  
S. Poertl ◽  
I. Liss ◽  
K. Mann ◽  
R. Hoermann
Keyword(s):  
Sialic Acid ◽  
Chorionic Gonadotropin ◽  
Human Chorionic Gonadotropin ◽  
Cho Cells ◽  
Acid Content ◽  
Tsh Receptor ◽  
Sialic Acid Content ◽  
Thyrotropic Activity

Mechanism of thyroid stimulation by human chorionic gonadotropin in sera of normal pregnant women

1991 ◽  
Vol 124 (2) ◽  
pp. 173-178 ◽  
Author(s):  
Masayoshi Yoshimura ◽  
Mitsushige Nishikawa ◽  
Norio Yoshikawa ◽  
Masateru Horimoto ◽  
Nagaoki Toyoda ◽  
...  
Keyword(s):  
Pregnant Women ◽  
Chorionic Gonadotropin ◽  
Human Chorionic Gonadotropin ◽  
Primary Hypothyroidism ◽  
Tsh Receptor ◽  
Thyroid Cell ◽  
Camp Accumulation ◽  
Binding Studies ◽  
Physiological Concentration ◽  
Thyrotropic Activity

Abstract. To elucidate the mechanism of thyrotropic activity of human chorionic gonadotropin in sera of normal pregnant women, we examined the effect of blockade of the TSH receptor on the serum-induced cAMP accumulation and the effect of hCG on the TSH binding to FRTL-5 cells. In the presence of crude immunoglobulin fractions in sera from patients with primary hypothyroidism, cAMP accumulation induced by both crude and purified hCG, and normal pregnant women serum were significantly inhibited compared with that in the presence of normal IgGs. The mode of inhibition of these IgGs on the cAMP accumulation was similar for TSH and hCG when analysed by Lineweaver-Burk plots. Moreover, binding of [125I]TSH to the TSH receptor in porcine thyroid cell membrane was apparently inhibited by adding 4×106 IU/l of purified hCG. Binding studies of TSH in FRTL-5 cells also indicated the dose-dependent displacements of [125I]TSH by hCG. Although half-maximal inhibitory- concentration of hCG was about 20 times as high as that of TSH on a molar basis, displacement of [125I]TSH was observed at a concentration of hCG of 105IU/l or more, which could be a physiological concentration of hCG in sera of normal pregnant women. These results suggest that thyrotropic activity of hCG in sera of normal pregnant women is, at least in a part, mediated by TSH receptors.

129: Sialic Acid Content of Urinary TAMM-Horsfall Protein is Reduced in Interstitial Cystitis Patients

2007 ◽  
Vol 177 (4S) ◽  
pp. 44-45
Author(s):  
C. Lowell Parsons ◽  
Mahadevan Rajasekaran ◽  
Marianne Chenoweth ◽  
Paul Stein
Keyword(s):  
Sialic Acid ◽  
Interstitial Cystitis ◽  
Acid Content ◽  
Sialic Acid Content

Effect of peptide nicking in the human chorionic gonadotropin β-subunit on stimulation of recombinant human thyroid-stimulating hormone receptors

1994 ◽  
Vol 130 (1) ◽  
pp. 92-96 ◽  
Author(s):  
Masayoshi Yoshimura ◽  
A Eugene Pekary ◽  
Xuan-Ping Pang ◽  
Loretta Berg ◽  
Laurence A Cole ◽  
...  
Keyword(s):  
Los Angeles ◽  
Chorionic Gonadotropin ◽  
Human Chorionic Gonadotropin ◽  
Hormone Receptors ◽  
Thyroid Stimulating Hormone ◽  
Human Thyroid ◽  
Β Subunit ◽  
Trophoblastic Diseases ◽  
Thyrotropic Activity ◽  
Stimulating Hormone

Yoshimura M, Pekary AE, Pang X-P, Berg L, Cole LA, Kardana A, Hershman JM. Effect of peptide nicking in the human chorionic gonadotropin β-subunit on stimulation of recombinant human thyroid-stimulating hormone receptors. Eur J Endocrinol 1994;130:92–6. ISSN 0804–4643 It is now generally accepted that human chorionic gonadotropin (hCG) has thyroid-stimulating activity. Heterologous forms of the hCG molecule occur in the purified preparations extracted from urine of pregnant women and patients with trophoblastic diseases. This work was undertaken to determine the effect of peptide nicking in the hCG-β subunit on its thyrotropic potency. Using Chinese hamster ovary cells expressing functional human thyroid-stimulating hormone (TSH) receptors, we examined the effect of nicked hCG on cyclic AMP (cAMP) production and receptor binding. The effect of human leukocyte elastase (hLE), a nicking enzyme, on standard hCG also was examined in the cAMP assay and on receptor binding. We studied five hCG preparations extracted from the urine of normal pregnancy (CR-127 and P8) and trophoblastic diseases (C2, C5 and M4). Two preparations (C2, 96% nicked and M4, 100% nicked in the β44–49 region) showed about a 1.5-fold potency of standard hCG CR-127, which is also 20% nicked in the same region. Non-nicked hCG (P8) had the weakest potency among all of the samples tested. Treatment of standard hCG with hLE increased the cAMP response about two-fold. Dose-dependent displacement of bovine [125I]TSH by standard hCG and hLE-digested hCG was observed and was almost identical. We have confirmed the increased in vitro thyrotropic activity of hCG nicked in the β-intercysteine loop on recombinant human TSH receptors. These data suggest that peptide heterogeneity of the hCG molecule may modulate the in vivo thyrotropic activity of hCG in pregnant women and patients with trophoblastic diseases. Jerome M Hershman, Endocrinology-W111D, West Los Angeles VA Medical Center, Los Angeles, California 90073, USA

scholarly journals Differences in Sialic Acid Content of Human Interferons

1978 ◽  
Vol 41 (1) ◽  
pp. 175-178 ◽  
Author(s):  
J. Morser ◽  
J. P. Kabayo ◽  
D. W. Hutchinson
Keyword(s):  
Sialic Acid ◽  
Acid Content ◽  
Sialic Acid Content

scholarly journals Infection with Listeria monocytogenes impairs sialic acid addition to host cell glycoproteins.

1994 ◽  
Vol 180 (6) ◽  
pp. 2137-2145 ◽  
Author(s):  
M S Villanueva ◽  
C J Beckers ◽  
E G Pamer
Keyword(s):  
Listeria Monocytogenes ◽  
Sialic Acid ◽  
Host Cell ◽  
Mhc Class I ◽  
Acid Content ◽  
Class I ◽  
Sialic Acid Content ◽  
Infected Cells ◽  
The Impact ◽  
Glycosylation Defect

Listeria monocytogenes is a facultative intracellular bacterium that causes severe disease in neonates and immunocompromised adults. Although entry, multiplication, and locomotion of Listeria in the cytosol of infected cells are well described, the impact of such infection on the host cell is unknown. In this report, we investigate the effect of L. monocytogenes infection on MHC class I synthesis, processing, and intracellular trafficking. We show that L. monocytogenes infection interferes with normal processing of N-linked oligosaccharides on the major histocompatibility complex (MHC) class I heavy chain molecule, H-2Kd, resulting in a reduced sialic acid content. The glycosylation defect is more pronounced as the infection progresses and results from interference with the addition of sialic acid rather than its removal by a neuraminidase. The effect is found in two different cell lines and is not limited to MHC class I molecules since CD45, a surface glycoprotein, and LGP120, a lysosomal glycoprotein, are similarly affected by L. monocytogenes infection. The glycosylation defect is specific for infection by L. monocytogenes since neither Trypanosoma cruzi nor Yersinia enterocolitica, two other intracellular pathogens, reproduces the effect. The resultant hyposialylation of H-2Kd does not impair its surface expression in infected cells. Diminished sialic acid content of surface glycoproteins may enhance host-defense by increasing susceptibility to lysis and promoting clearance of Listeria-infected cells.

scholarly journals Erythrocyte Sialic Acid Content during Aging in Humans: Correlation with Markers of Oxidative Stress

2012 ◽  
Vol 32 (3) ◽  
pp. 179-186 ◽  
Author(s):  
Mohammad Murtaza Mehdi ◽  
Prabhakar Singh ◽  
Syed Ibrahim Rizvi
Keyword(s):  
Oxidative Stress ◽  
Sialic Acid ◽  
Erythrocyte Membrane ◽  
Acid Content ◽  
Lipid Hydroperoxide ◽  
Plasma Lipid ◽  
Sialic Acids ◽  
Sialic Acid Content ◽  
Total Antioxidant ◽  
The Relationship

Sialic acids are substituted neuraminic acid derivatives which are typically found at the outermost end of glycan chains on the membrane in all cell types. The role of erythrocyte membrane sialic acids during aging has been established however the relationship between sialic acid and oxidative stress is not fully understood. The present work was undertaken to analyze the relationship between erythrocyte membrane sialic acid with its plasma level, membrane and plasma lipid hydroperoxide levels and plasma total antioxidant capacity. Results show that sialic acid content decreases significantly (P< 0.001) in RBC membrane (r= −0.901) and increases in plasma (r= 0.860) as a function of age in humans. Lipid peroxidation measured in the form of hydroperoxides increases significantly (P< 0.001) in plasma (r= 0.830) and RBC membranes (r= 0.875) with age in humans. The Trolox Equivalent Total Antioxidant Capacity (TETAC) of plasma was found to be significantly decreased (P< 0.001,r= −0.844). We observe significant correlations between decrease of erythrocyte membrane sialic acid and plasma lipid hydroperoxide and TETAC. Based on the observed correlations, we hypothesize that increase in oxidative stress during aging may influence the sialic acid decomposition from membrane thereby altering the membrane configuration affecting many enzymatic and transporter activities. Considering the importance of plasma sialic acid as a diagnostic parameter, it is important to establish age-dependent reference.

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