Fluctuations of physical function affected by sleep-awake rhythm--endocrine system

Pituitary hormone secretion is changed by sleep-awake rhythm, which also regulates by the hypothalamo-pituitary axis. The endocrine rhythm is also affected by such factors as aging and environment conditions. Nocturnal secretion of growth hormone is known to be induced by slow-wave sleep. Plasma prolactin levels seem to increase during REM sleep. Serum thyroid stimulating hormone levels increase during the night. Plasma adrenocorticotropin and cortisol levels increase in the early morning and decreased in the night, which are not related to the sleep stage. The sleep-related hormone secretion is not shown in the patients with disordered hypothalamo-pituitary axis. The evaluation of sleep-related changes in pituitary hormone is important to assess the hypothalamo-pituitary function.