National Association of Nutritional Professionals (NANP) Domain IV Practice Test

Graves disease is driven by antibodies that stimulate the TSH receptor on thyroid follicular cells. These thyroid-stimulating immunoglobulins bind the receptor and mimic the action of TSH, turning on the receptor’s signaling pathway. The result is increased production and release of thyroid hormones (T3 and T4) and growth of the thyroid, leading to hyperthyroidism and a goiter. The key idea is that the problem lies with antibodies targeting the TSH receptor, not with other thyroid proteins. Antibodies to TPO or thyroglobulin are associated with other autoimmune thyroid conditions and don’t drive the receptor signaling in Graves, and antibodies against the insulin receptor relate to diabetes, not Graves.