The Claim
In rodent models, genetic deficiency of the thyroid hormone transporter MCT8 is associated with enlarged testes and prolonged Sertoli cell proliferation, indicating that MCT8-mediated uptake of triiodothyronine (T3) normally serves to restrict testicular growth during development.
What the research says
Roughly balanced
Support and challenge are close. The picture may shift as more studies come in.
These are independent scores, not a percentage. Higher-grade studies count more, so a single strong opposing study can outweigh several weaker ones.
When baby rats don't have a special protein called MCT8 that helps thyroid hormone get into cells, their testicles grow bigger and keep growing longer than normal—suggesting this protein usually helps stop testicles from getting too big too fast.
See the scientific wording
In rodent models, genetic deficiency of the thyroid hormone transporter MCT8 is associated with enlarged testes and prolonged Sertoli cell proliferation, suggesting that MCT8-mediated T3 uptake normally limits testicular growth during development.
What the research says
1 studyStudy: Thyroid Hormone Deiodination and Action in the Gonads.
This study shows that a protein called MCT8 helps control how thyroid hormones affect testicle growth in young animals. If MCT8 doesn’t work right, the testicles might grow too much—just like the claim says.
Score breakdown, mechanism chain, raw evidence, ideal studies needed & 1 supporting studies
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