The molecular basis for epitopes on the free β-subunit of human chorionic gonadotrophin (hCG), its carboxyl-terminal peptide and the hCGβ-core fragment

Dirnhofer, Stephan; Madersbacher, S.; Bidart, Jean‐Michel; Kortenaar, Paul B. W. Ten; Spöttl, Gerald; Mann, Klaus; Wick, Georg; Berger, Peter

doi:10.1677/joe.0.1410153

Cited by 35 publications

(26 citation statements)

References 15 publications

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“…Production, purification and characterization of mabs recognizing hCG have been described previously [3, 4, 5, 6, 16, 17, 18, 19, 20, 21, 22]. With these mabs, 14 different epitopes were defined on the surface of dimeric preg-hCG: five on assembled hCGα (α 1 –α 5 ), five on assembled hCGβ (β 1 –β 5 ), and four that could be assigned to structures occurring only on the αβ-heterodimer (αβ 1 –αβ 4 ).…”

Section: Methodsmentioning

confidence: 99%

Tumor- and Pregnancy-Derived Isoforms of Human Chorionic Gonadotropin: Biological and Diagnostic Relevance

Lottersberger

Hoermann²,

Mann³

et al. 2003

Horm Res Paediatr

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Objectives: Human chorionic gonadotropin (hCG) and hCG variants are of high clinical importance for the diagnosis of pregnancy, monitoring of abnormal and ectopic pregnancies, testing for Down’s syndrome or monitoring therapy of hCG-secreting malignancies. In serum and urine, hCG appears in microheterogeneous isoforms with respect to protein backbone structure and the extent of glycosylation. The present study reports on the identification, immunological characterization, biological activity of glycosylation isoforms of pregnancy (preg) and tumor-derived (tu) hCG, and the impact of glycosylation on diagnostic immunoassays. Methods: Twenty-two urinary preg- and tu-hCG isoforms were separated by preparative isoelectrofocusing (hCG-pI variants) and characterized by Western blot. Number, topography and accessibility pattern of epitopes on their surface was evaluated by two-site radioimmunoassays using 14 different monoclonal antibodies (mabs). Binding of hCG isoforms to four different LH/CG receptors was investigated in radioreceptor assays, and their biological activity determined by measuring cAMP elevation. Results: All 22 hCG glycosylation variants appeared immunologically intact: each isoform, even when highly acidic, expressed all 14 surface epitopes which were arranged in a topographical manner indistinguishable from crude hCG. hCG isoforms were able to bind to four different receptor variants, with slightly varying affinities, but orientations indistinguishable from each other as shown by identical epitope accessibility patterns. Each of the hCG-pI variants was able to activate the LH/CG-Rs, but with varying reactivities. Conclusions: We conclude that in contrast to deglycosylated hCG, all hCG glycosylation isoforms investigated act as receptor agonists. Moreover, there is no overspecificity of mabs to certain hCG isoforms due to carbohydrate variability that exclude others from diagnostic measurement.

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Section: Methodsmentioning

confidence: 99%

Tumor- and Pregnancy-Derived Isoforms of Human Chorionic Gonadotropin: Biological and Diagnostic Relevance

Lottersberger

Hoermann²,

Mann³

et al. 2003

Horm Res Paediatr

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“…Plasma concentrations of FSH were determined by a double antibody ELISA assay for ovine samples, according to a previously described method (Faure et al 2005) using a monoclonal antibody against the ovine FSH b-subunit (Henderson et al 1995) for coating the microtitration plates and a biotinylated monoclonal antibody against the human a-subunit (Dirnhofer et al 1994) as a second antibody. Purified ovine FSH (NIH RP2) was used as the standard.…”

Section: Fshmentioning

confidence: 99%

Anti-Müllerian hormone as a predictive endocrine marker for embryo production in the goat

Monniaux¹,

Baril²,

Lainé³

et al. 2011

Reproduction

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Recently, we demonstrated the relationship between anti-Mü llerian hormone (AMH) circulating concentrations, ovarian follicles, and embryo production in cattle. However, they have not yet been established in a species with a seasonal breeding activity. Thus, goats were subjected to repeated in vivo embryo production during the breeding season, at the end of the breeding season, and at the end of the anestrus season. Embryo production after FSH treatment was highly repeatable for each goat. Plasma AMH concentrations, measured before the first FSH treatment, were highly correlated with the number of collected, transferable, and freezable embryos, resulting from the three sessions of embryo production. Plasma AMH concentrations transiently decreased after each exogenous FSH treatment, but they showed little change with season, and no relationship was observed between AMH and endogenous FSH concentrations during seasonal transitions. Follicles of 1-5 mm in diameter were the main target of the FSH treatment and were major contributors to circulating AMH concentrations. Granulosa cell AMH expression decreased as the follicle approached terminal development, while the expression of maturation markers (CYP19A1 and FSHR) increased. In conclusion, circulating AMH concentrations can be predictive of the capacity of a donor goat to produce high or low numbers of high-quality embryos. This prediction could be accurately made from a single blood measurement of AMH during either breeding or anestrus seasons. Variability in the number of gonadotropin-responsive follicles of 1-5 mm in diameter between individuals resulted in the differences in circulating AMH concentrations measured between individuals.

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“…Purified ovine LH (oLH CY1083) used as standard, controls and supernatants were added at 20 µl/ well along with 80 µl/well of dilution medium (PBS containing 0·09% Tween 20, 12·5% Sea-Block and 2% normal rat serum). Plates were incubated overnight at 4 C. After removal of unbound material, biotinylated monoclonal antibody to human -subunit (Dirnhofer et al 1994) diluted at 23 ng/100 µl/well in PBS containing 0·1% Tween 20 and 1% rat serum was added for 1 h at 37 C. Plates were washed and horseradish peroxidaselabelled neutravidin (Pierce) was added at 25 ng/100 µl/ well. After 25 min at room temperature in obscurity and washing, peroxidase activity was developed with 100 µl tetramethylbenzidine/well (Dako) for 30 min at room temperature.…”

Section: Lh and Fsh Assaysmentioning

confidence: 99%

BMP-4 inhibits follicle-stimulating hormone secretion in ewe pituitary

Faure¹,

Nicol²,

Fabre³

et al. 2005

Journal of Endocrinology

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Activins and inhibins, members of the transforming growth factor-beta family are able to stimulate and inhibit, respectively, FSH synthesis and release. Other members of this superfamily, the bone morphogenetic proteins (BMPs), may also affect FSH synthesis in the mouse. The aim of this work was to determine whether BMPs are expressed in the ovine pituitary and whether they play a role in the regulation of FSH release.The mRNAs encoding BMP-2, BMP-4, BMP-7 and the oocyte-derived growth factor, growth differentiation factor (GDF)-9 were detected in the pituitaries of cyclic ewes by reverse-transcriptase PCR, as well as the mRNAs encoding the BMP type I receptors, BMPR-IA (activinreceptor-like kinase (ALK)-3) and BMPR-IB (ALK-6), and type II receptors (BMPR-II). Immunolabeling of pituitary sections revealed the presence of BMPR-IA (ALK-3) and BMPR-II in gonadotrope cells. To investigate the potential effects of BMPs on FSH secretion, ewe pituitary cell cultures were treated with BMP-4 (10 11 M to 10 9 M) for 48 h. Interestingly, FSH release was decreased in a dose-dependent manner. At 10 9 M BMP-4 both FSH concentration and FSH mRNA expression were reduced by 40% of control values. In contrast, there was no inhibitory effect on either LH or LH mRNA expression. A similar result was found with BMP-6. BMP-4 triggered the phosphorylation of Smad1, suggesting that the effect of BMP-4 on FSH secretion is due to the activation of the BMPs signaling pathway. Furthermore, BMP-4 blocked the stimulatory effect of activin on both FSH release and FSH mRNA and amplified the suppression of FSH release and FSH mRNA levels induced by 17 -estradiol. These results indicate that a functional BMP system operates within the sheep pituitary, at least in vitro, to decrease FSH release and to modulate the effect of activin.

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The molecular basis for epitopes on the free β-subunit of human chorionic gonadotrophin (hCG), its carboxyl-terminal peptide and the hCGβ-core fragment

Cited by 35 publications

References 15 publications

Tumor- and Pregnancy-Derived Isoforms of Human Chorionic Gonadotropin: Biological and Diagnostic Relevance

Tumor- and Pregnancy-Derived Isoforms of Human Chorionic Gonadotropin: Biological and Diagnostic Relevance

Anti-Müllerian hormone as a predictive endocrine marker for embryo production in the goat

BMP-4 inhibits follicle-stimulating hormone secretion in ewe pituitary

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