Final answer:
Paraneoplastic hyperthyroidism can occur when human chorionic gonadotropin, produced by certain tumors, binds to thyroid-stimulating hormone receptors on the thyroid gland due to their structural similarity, leading to hyperthyroidism.
Step-by-step explanation:
Paraneoplastic hyperthyroidism can occur due to the structural similarity between two glycoprotein hormones: thyroid-stimulating hormone (TSH) and human chorionic gonadotropin (hCG). Normally, TSH is produced by the pituitary gland and controls the release of thyroid hormones thyroxine (T3) and triiodothyronine (T4) from the thyroid gland, located in the neck. In paraneoplastic syndromes, certain non-thyroidal tumors, such as those from the lung or breast, can produce hCG, which can sometimes bind to the TSH receptor on the thyroid gland due to their structural similarity. This binding can lead to overstimulation of the thyroid and excessive thyroid hormone production, resulting in clinical signs of hyperthyroidism such as weight loss, heat intolerance, and rapid heart rate.
Paraneoplastic hyperthyroidism can occur due to the structural similarity of thyroid-stimulating hormone (TSH) and thyroglobulin glycoprotein. Thyroid-stimulating hormone (TSH) is a hormone produced by the anterior pituitary that controls the release of thyroid hormones T3 and T4 from the thyroid gland. Thyroglobulin is a glycoprotein found in the thyroid that is converted into thyroid hormone. The structural similarity between these two glycoproteins can lead to the production of antibodies that target the thyroid-stimulating hormone receptors, resulting in overstimulation of the thyroid.