Permissive hormone regulation of hormone-sensitive effector systems

Thyroid hormones and glucocorticoids are examples of 'permissive' hormones that exert profound effects on the ability of cells to respond to other hormones, such as catecholamines. Catecholamines, like many other hormones whose activity is under the control of permissive hormones, bind to cell-surface receptors and activate the effector systems to which they are coupled via G proteins. Craig Malbon and colleagues analyse the mode of action of permissive hormones using the hormone-sensitive adenylate cyclase system as a model in tandem with the many new advances made in the understanding of the individual components of the system. New perspectives on permissive hormone action expressed at the level of receptors, G proteins, and effector systems provide a focal point for discussion of this intriguing level of hormonal regulation.