2001 S. Lincoln Ave. The thyroid gland exists in all mammals. It is a bi-lobed structure in the neck produces thyroid hormone. The main function of thyroid hormone is to regulate the metabolic rate in the body. Thyroid hormone affects every cell in the body.
Hyperthyroidism is the overproduction of thyroid hormone.
According to veterinarians at the University of Illinois College of Veterinary Medicine at Urbana, this is the most common endocrine disease in cats. It occurs in middle aged to older cats and has no breed or sex predisposition. There are two causes for the development of hyperthyroidism in cats. Most commonly, the thyroid gland will enlarge and begin to produce excess thyroid hormone without spreading to other parts of the body. The second cause is a diffuse enlargement of the thyroid gland, generally producing less thyroid hormone, but traveling to distant parts of the body.