Even in people with Graves’ disease, the thyroid still responds to its main hormone signal — TSH — by producing a key internal messenger, showing the system still works in lab tests.

Antibodies from people with Graves’ disease make thyroid cells way more active in a lab dish — like turning the volume up to 11 — by directly pushing the thyroid’s main control switch.

In Graves’ disease, the immune system makes faulty antibodies that trick the thyroid into overproducing hormones, causing it to go into overdrive.

When someone has Graves’ disease, their thyroid hormones get too high, which tells the brain to stop making a hormone that stimulates the thyroid — so that hormone ends up being very low or even missing in blood tests.

Steroid treatment with dexamethasone doesn’t stop the thyroid from responding to hormone signals in people with Graves’ disease — it seems to leave the gland’s inner workings untouched.

In Graves’ disease, there might be something else besides known triggers that’s revving up the thyroid — and dexamethasone could be affecting it, since the hormone changes happen too fast to be just from antibodies.