Which hormone is responsible for regulating basal metabolic rate?

Triiodothyronine, commonly known as T3, plays a critical role in regulating the body's basal metabolic rate (BMR). BMR refers to the amount of energy expended while at rest in a neutrally temperate environment, which reflects how efficiently the body uses energy. T3 is a thyroid hormone produced by the thyroid gland, and it has significant influence over metabolism by increasing the metabolic rate in cells.

When T3 levels are elevated, the body tends to burn more calories, utilize nutrients more efficiently, and maintain body temperature. It affects various physiological processes including the conversion of carbohydrates, proteins, and fats into energy. An adequate level of T3 is essential for proper growth, development, and overall metabolism.

Considering the other hormones listed, insulin primarily regulates glucose levels in the blood rather than BMR, cortisol is involved in stress response and metabolism but does not directly regulate BMR, and adrenaline (also known as epinephrine) is involved in the fight-or-flight response, temporarily increasing metabolic activity but not maintaining BMR. Therefore, T3 is specifically aligned with the function of regulating basal metabolic rate.