Molecular Mechanisms of Thyroid Hormone-stimulated Steroidogenesis in Mouse Leydig Tumor Cells

Thyroid hormone doesn’t directly make sex hormones like testosterone or estrogen, but it helps the body’s sex glands work properly so they can produce these hormones at the right levels.

A hormone called T3 makes certain mouse cancer cells produce more of a key protein and more of the hormone progesterone, as if it’s turning up the volume on both the recipe and the final product.

When there’s too much of a protein called DAX-1 in mouse testicle cells, it blocks the thyroid hormone from doing its job—preventing the cells from making progesterone, a hormone needed for reproduction.

A hormone called T3 makes normal mouse testicle cells produce more testosterone, which means it doesn’t just work in cancer cells—it also works in healthy ones.

Two different hormones, T3 and hCG, both make a key protein (StAR) in mouse testicle cells work harder to produce steroids, and when you use both together, they boost it even more — like two different keys that each unlock the same door, and using both at once opens it wider.

A thyroid hormone called T3 turns up a gene called SF-1 in mouse testicle cells, and without SF-1, T3 can’t make the cells produce sex hormones—so SF-1 is like a middleman helping the hormone do its job.