Related Experiment Videos
Physiologic thyroid activation in normal early pregnancy is induced by circulating hCG
1Department of Laboratory Medicine, Osaka University Medical School, Japan.
Obstetrics and Gynecology
|May 1, 1990
Summary
Human chorionic gonadotropin (hCG) activates the thyroid gland during early pregnancy. This study found that hCG in pregnant women
Area of Science:
- Endocrinology
- Reproductive Biology
- Thyroid Research
Background:
- Thyroid hormone levels (free thyroxine [T4]) increase and thyroid-stimulating hormone (TSH) decreases in early pregnancy.
- The physiological mechanism behind this thyroid activation is not fully understood.
Purpose of the Study:
- To identify the specific factor responsible for thyroid gland activation in early pregnancy.
- To investigate the role of human chorionic gonadotropin (hCG) in this process.
Main Methods:
- Serum samples from 39 pregnant women were analyzed for thyroid-stimulating activity.
- A sensitive cyclic adenosine 3',5'-monophosphate (cAMP) accumulation assay using a rat thyroid cell line (FRTL-5) was employed.
- Serum hCG levels were measured and compared with thyroid-stimulating activity.
Main Results:
- Thyroid-stimulating activity was detected in 95% of pregnant women.
- This activity positively correlated with serum free T4 and negatively with serum TSH levels.
- Serum thyroid-stimulating activity showed a strong positive correlation with serum hCG levels and was neutralized by hCG antibodies.
Conclusions:
- Human chorionic gonadotropin (hCG) possesses intrinsic thyroid-stimulating activity.
- hCG is the primary factor responsible for physiological thyroid activation in normal early pregnancy.