What is the major function of thyroxin?

Thyroxin, also known as T4, plays a crucial role in the regulation of metabolism in the body. This hormone, produced by the thyroid gland, primarily influences how the body uses energy. It increases the metabolic rate, which affects processes such as how quickly the body converts food into energy, how it burns fat, and the overall speed of bodily functions.

Metabolism encompasses all the biochemical processes that occur within the body, including the synthesis and breakdown of substances. Thyroxin stimulates the metabolic rate of almost every cell in the body, leading to increased energy expenditure and influencing growth and development.

In contrast, the other functions outlined in the options relate to different hormones and systems. Blood pressure regulation involves hormones such as adrenaline and aldosterone, while calcium levels are primarily regulated by parathyroid hormone and calcitonin. Glucose levels are managed by insulin and glucagon from the pancreas. While these processes are vital, they are not the primary function of thyroxin, which distinctly focuses on metabolism.