Which category of hormones does thyroid hormone belong to?

Thyroid hormones belong to the category of peptide hormones. They are important hormones secreted by the thyroid gland and play a crucial role in maintaining normal metabolism and growth and development in the human body. Thyroid hormones exist in various forms, including total T3, total T4, free T3, and free T4. Their synthesis and secretion are regulated by thyroid-stimulating hormone (TSH) released by the pituitary gland.

The secretion of thyroid hormones is precisely controlled by the hypothalamic-pituitary-thyroid axis to ensure their blood concentrations remain within the normal range. Abnormally high or low levels of thyroid hormones can have adverse effects on health, such as hyperthyroidism or hypothyroidism. Therefore, maintaining a balanced state of thyroid hormones is important for human health.

The main functions of thyroid hormones include promoting metabolism, increasing thermogenic effects, elevating the body's oxygen consumption, and significantly influencing the metabolism of carbohydrates, fats, and proteins. Additionally, thyroid hormones promote the development and maturation of the nervous system and also facilitate bone growth and development. Thus, thyroid hormones play multiple roles in the human body and are among the key hormones required for maintaining normal physiological functions.