Hormone Receptors and Hormonal Regulation of Macrophage Physiological Functions

摘要

Interaction of hormones with their specific receptors is the first step in their biological activity in virtually every target tissue. Hormones may act directly or via second messengers to regulate functions of membranes and proteins and to induce differential gene expression. Thus identification and characterization of hormone receptors is essential in the analysis of molecular mechanisms of hormonal regulation of cellular function. The mononuclear phagocytes are important cells for the study of these mechanisms. First, monocytes and macrophages from man and experimental animals are easily obtained in pure populations and can be maintained in culture for extended periods. With the macrophage as a model, the role of hormone receptors can then be evaluated in several physiological (e.g., aging) and pathological (e.g., obesity, inflammation) states. Second, since hormones regulate the availability and several basic functions of macrophages, molecular insight is gained concerning the participation of macrophages in inflammation and cellular immunity. By criteria of either binding or alterations of function, macrophages could potentially contain receptors for several hormones. The evidence for binding of polypeptide hormones, steroids, catecholamines, and other hormones to receptors in mononuclear phagocytes is reviewed, characterizing the hormone receptors for glucocorticoids and insulin, which are the only ones that have been investigated in detail. Some of the physiological consequences of binding of these hormones by macrophage target cells are discussed. (ERA citation 04:014573)