Which hormone stimulates the division of cells and is usually secreted the most during sleep?

Growth hormone is primarily responsible for stimulating cell division and is involved in tissue growth and muscle development. Its secretion is significantly increased during sleep, particularly during the deep stages of non-REM sleep. The surge in growth hormone during these sleep phases plays a critical role in the body's recovery, repair processes, and overall growth.

This hormone promotes the growth of bones and tissues and helps to regulate metabolism by influencing the way the body uses fats and carbohydrates. Its peak secretion during sleep emphasizes the importance of restorative sleep for growth and regeneration. In contrast, other hormones listed, although important in various physiological processes, do not primarily stimulate cell division or have the same pronounced nocturnal secretion pattern as growth hormone.