The broad objectives of this project are to understand the transport of hormones to target tissues, the biological functions of binding proteins, and the mechanisms by which they are regulated in human disease. Recent research findings include: Demonstration that a substantial component of blood cortisol is transported within erythrocytes and that the erythrocyte- associated cortisol dissociates extremely rapidly and would therefore be readily available to tissues; and elucidation of new evidence supporting a role for protein-bound plasma hormones, by dint of their bioavailability, in the regulation of hepatic functions. No future studies are planned under this project.