Written by the Fiveable Content Team • Last updated September 2025
Written by the Fiveable Content Team • Last updated September 2025
Definition
Thyroid-stimulating immunoglobulin (TSI) is an antibody that mimics thyroid-stimulating hormone (TSH), leading to overstimulation of the thyroid gland. It is commonly associated with Graves' disease, an autoimmune disorder.
5 Must Know Facts For Your Next Test
TSI is responsible for the hyperthyroidism seen in Graves' disease.
It binds to TSH receptors on the thyroid gland, causing excess production of thyroid hormones.
Elevated levels of TSI can be detected through specific blood tests.
Patients with high TSI levels often present symptoms such as weight loss, rapid heartbeat, and bulging eyes.
Management of conditions involving TSI typically includes antithyroid medications or treatments aimed at reducing thyroid activity.
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Related terms
Graves' Disease: An autoimmune disorder characterized by hyperthyroidism due to excessive stimulation by TSI.
Thyroid-Stimulating Hormone (TSH): A hormone produced by the pituitary gland that regulates thyroid function.
Hyperthyroidism: A condition where the thyroid gland produces too much thyroid hormone, often due to conditions like Graves' disease.