Selected Autacoids as Modulators of Lymphocyte Function

Abstract

Autacoids are biologic mediators of increasing importance. Their name derives from the Greek autos meaning self and akos meaning medicinal agent. They are ubiquitously distributed, that is, they are found in most tissues and body fluids, and they regulate a variety of major physiologic functions and participate in some well-defined pathologic processes. Although autacoids have been defined as auto-hormones, they differ from hormones in that they are made, play their role, and are destroyed at the same sites. Many tissues make, respond to, and metabolize autacoids. The substances ordinarily are not transported for their physiologic effects; they usually regulate the function of a tissue system in the vicinity of their synthesis and are also metabolized in the same region. But in some pathologic states, excessive amounts of autacoids can reach the systemic circulation and account for many of the symptoms of the disorder (e.g., in the carcinoid syndrome and in patients with pheochromocytoma syndrome; M(elmon 1981). With this definition of autacoids, it is not surprising that histamine, catecholamines, and prostaglandins can be included in this class of mediator. Biologically active peptides and lymphokines will no doubt be subsumed in future textbook classifications of autacoids (Fig. 1).