Interaction of human chorionic gonadotropin (hCG) and asialo-hCG with recombinant human thyrotropin receptor.

Hoermann, Rudolf; Broecker, M.; Grossmann, Mathis; Mann, Klaus; Derwahl, Michael

doi:10.1210/jcem.78.4.8157724

Cited by 20 publications

(17 citation statements)

References 37 publications

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“…It is well established that hCG is a putative thyroid stimulator. The thyrotropic activity of hCG in normal pregnant women is, at least in a part, mediated by TSH receptors [20]. An abnormal interaction of hCG and TSH hormones early in pregnancy may be a factor causing different rates of subclinical hypothyroidism in different populations.…”

Section: Discussionmentioning

confidence: 99%

Prevalence and risk factors for hypothyroidism in Jordanian women: comparison between different reference ranges

Alkafajei

Amarin²,

Alazaizeh³

et al. 2012

East Mediterr Health J

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The aim of this cross-sectional study in Jordan was to estimate the prevalence of hypothyroidism among women during early pregnancy and to assess the association of risk factors with hypothyroidism. According to internationally adopted thyroid stimulating hormone (TSH) and thyroxine (T 4 ) pregnancy reference ranges (TSH ≥ 2.6 mIU/L and T 4 10.6-20.4 pmol/L), 67 of 322 (20.8%) women were diagnosed with sub-clinical hypothyroidism. When the general laboratory criteria were applied (TSH ≥ 4.6 mIU/L and T 4 < 10.6 pmol/L) the prevalence dropped to 4.3%. No cases of overt hypothyroidism were diagnosed using either diagnostic criterion. Younger age and being in gestational weeks 1-8 were significant risk factors for hypothyroidism. It is suggested that the reference criteria need revision, and that pathology laboratories should adopt appropriate pregnancyspecific reference intervals.

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Section: Discussionmentioning

confidence: 99%

Prevalence and risk factors for hypothyroidism in Jordanian women: comparison between different reference ranges

Alkafajei

Amarin²,

Alazaizeh³

et al. 2012

East Mediterr Health J

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“…This 'hyperthyroidism with suppressed TSH' is known with patients suffering Graves' disease, hyperemesis gravidarum, and trophoblastic diseases. The pathogenic agents causing these diseases have been identified: thyroid-stimulating antibodies in Graves' disease, excess levels of human chorionic gonadotropin (hCG) and in hyperemesis gravidarum (Lao et al 1988, Rodien et al 1998 and in trophoblastic diseases (Nisula & -Ketelslegers 1974, Nisula & Taliadouros 1980, Hoermann et al 1994. Recently, two cases of goitrous euthyroid patients presenting low TSH have been reported (Ikekubo et al 2005).…”

Section: Discussionmentioning

confidence: 99%

Differential expression of the thyrostimulin subunits, glycoprotein 2 and 5 in the rat pituitary

Nagasaki

Wang

Jackson

et al. 2006

Journal of Molecular Endocrinology

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Two glycoprotein hormone subunits, (glycoprotein hormone a2-subunit GPA2) and (glycoprotein hormone b5-subunit GPB5) have been recently discovered which, when expressed in vitro, heterodimerize to form a new hormone called thyrostimulin. Thyrostimulin activates the thyroid-stimulating hormone receptor (TSHR) and has thyrotropic activity. Immunological studies have indicated that both subunits co-localize in pituitary cells. To explore the function of thyrostimulin in the rat, we have cloned rat GPA2 and GPB5, reconstituted the heterodimers in vitro, and confirmed that rat thyrostimulin activates TSHR with an affinity similar to that of TSH. In situ hybridization of the pituitary showed that while GPA2 is expressed in the anterior lobe, GPB5 is not detected in any of the lobes. A quantitative analysis showed that the co-localization of GPA2 and GPB5 is restricted in the rat to the eye and the testis. We found that GPB5 can be detected in the pituitary by quantitative-PCR, but at extremely low levels, 2000-fold lower than TSH b-subunit (GPBtsh). Furthermore, the levels of GPB5 remain constant during the estrus cycle, while those of GPA2 vary. Finally, we found that none of the thyrostimulin subunits was induced by TRH in pituitary cell culture. These data point at the thyrostimulin system as being functionally different to the TSH system.

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“…Various degradation processes take place on the branched carbohydrate side chain (Kraiem et al ., 1997). It has been found that desialylation enhances the binding affinity of hCG to TSH receptors and consequently lead to higher thyrotrophic activity (Amir et al ., 1987; Hoermann et al ., 1991; Hoermann et al ., 1993; Hoermann et al ., 1994; Yamazaki et al ., 1995; Kraiem et al ., 1997). However, in contrast, a recent study suggested that it is acidic isoforms of hCG which are implicated in hyperemesis gravidarum (Jordan et al ., 1999).…”

Section: Discussionmentioning

confidence: 99%

Prevalence of gestational thyrotoxicosis in Asian women evaluated in the 8th to 14th weeks of pregnancy: correlations with total and free beta human chorionic gonadotrophin

Yeo¹,

Khoo

Eng

et al. 2001

Clinical Endocrinology

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Using sensitive assays, the prevalence of gestational thyrotoxicosis in Asian women was found to be 11.0% and was significantly higher in subjects at 8-11 weeks of gestation than at 12-14 weeks. The positive correlation between hCG and free T4 seen in patients tested at 8-11 weeks was absent in patients tested at later stages of the first trimester. Future studies investigating the entity of gestational thyrotoxicosis, at least in Asian patients, should focus on patients at earlier stages of gestation than currently practised.

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Interaction of human chorionic gonadotropin (hCG) and asialo-hCG with recombinant human thyrotropin receptor.

Abstract: hCG is a putative thyroid stimulator. The present studies were undertaken to examine its interaction and that of its desialylated

Cited by 20 publications

References 37 publications

Prevalence and risk factors for hypothyroidism in Jordanian women: comparison between different reference ranges

Prevalence and risk factors for hypothyroidism in Jordanian women: comparison between different reference ranges

Differential expression of the thyrostimulin subunits, glycoprotein 2 and 5 in the rat pituitary

Prevalence of gestational thyrotoxicosis in Asian women evaluated in the 8th to 14th weeks of pregnancy: correlations with total and free beta human chorionic gonadotrophin

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