What is Corticosteroid-Binding Globulin?

Cortisol-binding globulin (CBG) is a serum alpha-2-globulin-binding protein with high affinity and limited capacity for cortisol. It binds most (±92%) of the serum cortisol; the remaining cortisol (±8%) circulates in a free form or bound to albumin.

Cortisol-binding globulin (CBG) is synthesized in the liver. Circulating levels increase in pregnancy or after administration of estrogen or oral contraceptives. Insulin may inhibit synthesis, a fact that might explain the low CBG levels observed in hyperinsulinemic states (eg, diabetes, obesity, PCO).

Cortisol-binding globulin (CBG) levels are also reduced in:

  • nephrotic syndrome,
  • starvation,
  • severe chronic liver disease.

The Cortisol-binding globulin (CBG) assay is helpful in assessing unexpected values of blood cortisol. Other assays useful in diagnosis and therapy of cortisol abnormalities include plasma cortisol, ACTH, β-lipotropin, urinary cortisol (by HPLC), or free cortisol in plasma or serum.


The information on is NOT intended to replace a one-on-one relationship with a qualified health care professional and is not intended as medical advice.

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.

%d bloggers like this: