Hyperthyroidism is the term for overactive tissue within the thyroid gland, resulting in overproduction and thus an excess of circulating free thyroid hormones: thyroxine, triiodothyronine (T3), or both . Thyroid hormone is important at a cellular level, affecting nearly every type of tissue in the body. It functions as a stimulus to metabolism, and is critical to normal function of the cell. In excess it overstimulates, causing "speeding up" of various body systems, and thus symptoms: Fast heart beat results in palpitations, a fast nervous system in tremor and anxiety symptoms, a fast digestive system in weight loss and diarrhea.
Hyperthyroidism may depend on increased production of:
- Antibodies against TSH receptor
- T3 from T4
T3 from T4
Phosphodiesterase 8B gene variants are associated with serum TSH levels and thyroid function. 2008
Hyperthyroidism Overview at endocrineweb