Thyroid System

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The thyroid regulates metabolism.
The two main thyroid hormones are T3 and T4.
Thyroid disorders are common in dogs, and include hypothyroidism and thyroiditis.

The Thyroid’s Main Function

The thyroid’s main role in the endocrine system is to regulate metabolism, which is the body’s ability to break down food and convert it to energy. Food essentially fuels our bodies, and our bodies each “burn” that fuel at different rates.

The thyroid keeps the metabolism under control through the action of thyroid hormone, which is made by extracting iodine from the blood and incorporating it into thyroid hormones. Thyroid cells are unique in that they are highly specialized to absorb and use iodine.

Every other cell depends on the thyroid to manage its metabolism.The pituitary gland and hypothalamus both control the thyroid. When thyroid hormone levels drop too low, the hypothalamus secretes TSH Releasing Hormone (TRH), which alerts the pituitary to produce thyroid stimulating hormone (TSH). The thyroid responds to this chain of events by producing more hormones.

Diseases and Disorders of the Thyroid

There are several diseases and disorders associated with the thyroid. They can develop at any age and can result from a variety of causes injury, disease, or dietary deficiency, for instance. But in most cases, for dogs, they can be traced to two of the most common canine thyroid disorders.

Hypothyroidism: Hypothyroidism is a common condition characterized by too little thyroid hormone and often goes unnoticed, sometimes for years, before being diagnosed.
Thyroiditis: Thyroiditis is an inflammation of the thyroid that can cause the thyroid’s cells to die, making the thyroid unable to produce enough hormones to maintain the body’s normal metabolism.

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