Other cells that contain hemoglobin include the A9 dopaminergic neurons in the substantia nigra, macrophages, alveolar cells, and mesangial cells in the kidney. In these tissues, hemoglobin has a non-oxygen-carrying function as an antioxidant and a regulator of iron metabolism.
The opposite is hypothyroidism, when the thyroid gland does not make enough thyroid hormone. Graves' disease is the cause of about 50% to 80% of case of hyperthyroidism in the United States. Other causes include multinodular goiter, toxic adenoma, inflammation of the thyroid, eating too much iodine, and too much synthetic thyroid hormone.
Overproduction or underproduction of a pituitary hormone will affect the respective end-organ. For example, insufficient production (hyposecretion) of thyroid stimulating hormone (TSH) in the pituitary gland will cause hypothyroidism, while overproduction (hypersecretion) of TSH will cause hyperthyroidism.or example, insufficient production (hyposecretion) of thyroid stimulating hormone (TSH) in the pituitary gland will cause hypothyroidism, while overproduction (hypersecretion) of TSH will cause hyperthyroidism.