Cortisol

Cortisol is secreted by the adrenal cortex band and exists in the blood in two forms, bound and free. Cortisol in the free state only accounts for about 10%, is biologically active and can be filtered from the kidney; those in the bound state are mainly combined with glucocorticosteroid-binding protein (CBG), and a small amount of albumin, have no biological activity and are Hepatocytes are damaged and cannot be filtered from the glomeruli. The secretion of cortisol is mainly regulated by the pituitary gland corticotropin. Its secretion has a clear circadian rhythm. The secretion reaches a peak around 8 am, and then gradually decreases, with the lowest at midnight. Cortisol has very important effects on the body's material metabolism, immune function, and physiological functions of various organs.