Document Detail

Human chorionic gonadotropin may not be responsible for thyroid-stimulating activity in normal pregnancy serum.
MedLine Citation:
PMID:  1730805     Owner:  NLM     Status:  MEDLINE    
Although hCG can activate thyroid cells in culture there is considerable doubt as to whether it is responsible for the changes in thyroid function which occur during normal pregnancy. Thyroid-stimulating activity (TSA), measured using iodide uptake into FRTL-5 cells, was demonstrated in 32/51 (63%) first and 15/29 (52%) third trimester sera. Free T3 was increased (P less than 0.001) and TSH decreased (P less than 0.01) in first trimester. In the early pregnancy group there was a positive correlation between hCG and TSA (r = 0.594, P less than 0.001) and a negative correlation between hCG and TSH (r = -0.329, P less than 0.02). In third trimester hCG concentration was often below that required to produce TSA in vitro and TSA could not be neutralized by antibodies to hCG. There was no correlation between hCG and TSH or thyroid hormones in the third trimester. In 26 women TSA decreased in parallel with serum hCG concentration after termination of pregnancy (P less than 0.001). Free T3 also decreased (P less than 0.01) and TSH increased (P less than 0.05) after termination. TSA persisted in many patients even after hCG was either very low or undetectable. Purified hCG stimulated iodide uptake in a concentration-dependent manner. Stimulation of iodide uptake by TSH was inhibited by the simultaneous presence of low concentrations of hCG while activity was restored with high concentrations. hCG may contribute to the thyroid changes in early pregnancy. However the poor correlation between TSA and thyroid tests suggests that other factors may be involved. The partial agonist activity of hCG may account for some of the inconsistencies observed but TSA in serum from late pregnancy or after termination of pregnancy is almost certainly due to another hormone or growth factor.
R L Kennedy; J Darne; M Cohn; A Price; R Davies; A Blumsohn; H Griffiths
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  The Journal of clinical endocrinology and metabolism     Volume:  74     ISSN:  0021-972X     ISO Abbreviation:  J. Clin. Endocrinol. Metab.     Publication Date:  1992 Feb 
Date Detail:
Created Date:  1992-02-18     Completed Date:  1992-02-18     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0375362     Medline TA:  J Clin Endocrinol Metab     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  260-5     Citation Subset:  AIM; IM    
Department of Medicine, Northern General Hospital, Sheffield, United Kingdom.
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MeSH Terms
Analysis of Variance
Cell Line
Chorionic Gonadotropin / pharmacology,  urine*
Iodides / metabolism*
Pregnancy / blood*
Pregnancy Trimester, First
Pregnancy Trimester, Third
Reference Values
Thyroid Gland / physiology*
Reg. No./Substance:
0/Chorionic Gonadotropin; 0/Iodides

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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