A brief survey will be made of the characteristics of the physicochemical methods that have been used to study the binding of steroid hormones by plasma protein. There is now considerable evidence obtained by several laboratories indicating that 2 plasma proteins are responsible for most of the binding of steroids:
1. Albumin is the principal binding protein for the less polar steroids, (androgens, estrogens, and progesterone). Despite its polar characteristic, bound aldosterone of plasma is primarily associated with this protein.
2. The corticosteroid binding globulin (CBG), sometimes called "transcortin," is an alpha glycoprotein that has a high affinity for the