Cortisol is a glucocorticosteroid, which affects protein, fat and carbohydrate metabolism. Cortisol stimulates gluconeogenesis in the liver, inhibits the effect of insulin on muscle cells and decreases the rate at which cells use glucose. Secretion of cortisol is greatest between 6:00 and 8:00am and lowest between 4:00 and 6:00pm. Cortisol is increased in hyperfunctioning adrenals and decreased in hypofunctioning adrenals.
Cortisol levels are increased in:
- Hyperthyroidism
- Stress
- Carcinoma
- Adrenal adenoma
- Obesity
- Overproduction of ACTH
- Cushing’s syndrome
Cortisol levels are decreased in:
- Adrenal hyperplasia
- Addison disease
- Anterior pituitary hyposecretion of ACTH
- Hypothalamus hyposecretion of ACTH releasing hormone
- Hypothyroidism
- Patients on prednisone or steroids
- Oral contraceptives
Normal Range
4 pm 3-16 ug/dL 83-441 nmol/L