Human growth hormone is secreted by the pituitary growth hormone cells, which can promote the synthesis of various tissues in the human body, especially protein, and can stimulate the cartilage of bone and joint and epiphyseal cartilage to promote the growth and development of the human body. Its secretion has the following characteristics: 1. Pulsatile secretion, with large fluctuations between day and night: the number of growth hormone pulses in prepubescent and adolescent adolescents is about 6-8 times in 24 hours, with an average of 3-4 hours. The frequency of secretion is more at night than during the day, and growth hormone secretion is most vigorous about 1 hour after deep sleep, while it is often lower than 5ug/l during the day, so the randomly measured growth hormone level during the day is not very meaningful. 2. Circadian rhythm: The peak secretion of growth hormone pulse can occur 45-90 minutes after normal people fall asleep, which can reach up to 50-60ug/l, especially when deep sleep state is more obvious. Children who want to grow taller should ensure sufficient and high quality sleep. 3, the influence of exercise: exercise can stimulate growth hormone, normal people can hardly measure growth hormone in their blood when they just wake up, but after waking up, light activity can stimulate growth hormone secretion, and after strenuous exercise can stimulate growth hormone peak. This is the basis of growth hormone exercise test, and also the reason why we let children with short stature exercise more. 4, the influence of stress state: surgery, trauma, anesthesia, puncture, tension, anxiety and other stimuli can promote growth hormone secretion, but reversible growth hormone secretion inhibition can also occur when the stimulus is too strong. 5. Metabolic substances: Acute hypoglycemia is a strong factor to stimulate growth hormone secretion, so we often use insulin to stimulate children to have hypoglycemia by static push, and then measure their blood growth hormone level to determine whether they have growth hormone deficiency. A high protein diet can stimulate growth hormone secretion, while elevated levels of free fatty acids can inhibit the release of growth hormone.