What Is the Connection Between Cortisol and Sleep?
Plasma cortisol measurement refers to the measurement of plasma cortisol.
Determination of plasma cortisol
Right!- Plasma cortisol measurement refers to the measurement of plasma cortisol.
- Plasma cortisol is a glucocorticoid secreted by the adrenal cortex band. Normal human plasma cortisol is regulated by ACTH and has a certain circadian rhythm. Generally, the secretion is the lowest at about 1 o'clock in the morning or early in the morning, and the plasma content is the lowest. The secretion starts to increase at 4 am, and the secretion is the highest at 6-8 am. Secretion gradually decreases after 8 o'clock, and the secretion volume around 5 o'clock in the afternoon decreases by 50% or more than the highest value in the morning. Cortisol, which is secreted into the blood circulation, exists in free and protein-bound form, called total plasma cortisol. Protein-bound cortisol accounts for more than 90% of the total plasma cortex, has no biological activity, cannot enter cells, and is not catabolized and filtered by the glomerulus when passing through the liver; free cortisol has biological activity and can enter cells It is metabolized and inactivated in the liver, and can be filtered into the urine through the glomerulus. The content of free cortisol in urine is directly proportional to the content of free cortisol in plasma. When the total plasma cortisol level rises above the binding limit with corticosteroid-binding globulin, the level of free cortisol in the plasma rises, followed by a sharp rise in the excretion of free cortisol in the urine.
- Venous blood was taken at 8 am, 5 pm, and 12 midnight to determine plasma free cortisol levels. Or take 24h urine to determine the level of free cortisol.
- Pregnancy, oral contraceptives: elevated estrogen causes increased corticosteroid binding globulin.
- Stress: Plasma cortisol is elevated, but the rhythm is normal.
- The circadian rhythm of the blind, night shift, and poor sleep disappeared.
- Sodium phenytoin, sodium salicylate, central antihypertensive drugs, and sedatives can reduce cortisol levels.