Here's why:
* Thyroid hormone is produced by the thyroid gland and plays a crucial role in regulating metabolism.
* T4 and T3 bind to receptors inside cells, activating genes that control the production of proteins involved in cellular processes like:
* Energy production: Increasing the rate of glucose and fat metabolism.
* Growth and development: Promoting cell growth and differentiation.
* Heart rate and blood pressure: Increasing both.
* Body temperature: Maintaining a stable core temperature.
Other hormones can also influence metabolic rate, but to a lesser extent than thyroid hormone. These include:
* Growth hormone: Promotes protein synthesis and growth.
* Insulin: Promotes glucose uptake and storage.
* Glucagon: Increases blood glucose levels.
* Epinephrine (adrenaline): Increases energy production in short bursts.
Therefore, thyroid hormone is the primary regulator of metabolic rate in the body.
