Molecular Aspects of Hormone Regulation

Hormones travel in the bloodstream to exert effects on target tissues, which are often anatomically remote from the site of hormone secretion. They achieve this by binding and activating receptors, which usually are highly selective or specific. Receptors are grouped into several families according to their molecular structure and mechanism of action. Common classes of receptors important in endocrinology include cell surface G-protein-coupled receptors, receptor tyrosine kinases, and cytokine-like receptors, and intracellular nuclear hormone receptors. In this chapter the basic anatomy of the signalling pathways emanating from these receptors is described, and the principles and mechanisms of information coding and transmission, and how these may go awry in endocrine disease, are discussed.