The thyroid gland, located in the neck, secretes thyroid hormones which regulate metabolism. Thyroid stimulating hormone produced by the pituitary gland signals the thyroid to absorb iodine and produce thyroxine and triiodothyronine. These hormones increase metabolism by stimulating mitochondria and cellular respiration. Conditions like Hashimoto's disease can cause hypothyroidism by impairing thyroid function, while Graves' disease causes hyperthyroidism through uncontrolled thyroid hormone production. Hypothyroidism is treated with synthetic thyroid hormone replacement drugs like levothyroxine, while hyperthyroidism is treated with anti-thyroid drugs that inhibit hormone synthesis or radioactive iodine therapy.

1. Thyroid and Anti-Thyroid Drugs An overview of the thyroid, thyroid drugs, and the mechanisms through which they affect thyroid function.