Thyroxine replacement modifies changes in deiodinase and thyroid hormone transporter expression induced by subclinical hypothyroidism in rats.
Hormones (Athens)
; 20(1): 101-110, 2021 Mar.
Article
in En
| MEDLINE
| ID: mdl-32996026
ABSTRACT
PURPOSE:
The potential benefits of treating subclinical hypothyroidism (SCH) are unclear and still controversial. Thus, we surgically induced SCH in rats and evaluated the effects of thyroxine (T4) replacement on the gene expression levels of deiodinases and thyroid hormone (TH) transporters in different tissues.METHODS:
SCH was induced by hemithyroid electrocauterization. The control animals underwent the same surgical procedure but were not subjected to electrocauterization (sham). After 14 days, half of the SCH animals were treated with T4 (SCH + T4). At the end of the experimental protocol, all of the rats were euthanized, serum hormone concentrations were measured, and RNA analyses were performed on different tissues and organs.RESULTS:
Consistent with previous studies, we observed increased TSH levels, normal TH levels, and reduced hypothalamic TRH expression in the SCH group. Additionally, Dio2 mRNA expression was downregulated in the hippocampus and pituitary, and Dio1 was upregulated in the kidney and pituitary of the SCH animals. The changes in Dio3 expression were tissue-specific. Concerning TH transporters, Mct10 expression was upregulated in the pituitary, kidney, hypothalamus, and hippocampus, and Mct8 expression was downregulated in the kidney of the SCH group. Crym expression was upregulated in the kidney and pituitary. Notably, T4 replacement significantly attenuated serum TSH levels and reverted Dio1, Dio2, Mct10, and Crym expression in the pituitary, hippocampus, and kidney to levels that were similar to the sham group. Tissue-specific responses were also observed in the liver and hypothalamus.CONCLUSION:
Our results indicate that treatment of SCH should be considered before the appearance of clinical symptoms of hypothyroidism.Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Thyroxine
/
Thyroxine-Binding Proteins
/
Hypothyroidism
/
Iodide Peroxidase
Type of study:
Etiology_studies
/
Guideline
Limits:
Animals
Language:
En
Journal:
Hormones (Athens)
Journal subject:
ENDOCRINOLOGIA
Year:
2021
Document type:
Article
Affiliation country:
Brasil
Publication country:
CH
/
SUIZA
/
SUÍÇA
/
SWITZERLAND