Eicosanoids are a diverse group of bioactive lipid molecules derived from polyunsaturated fatty acids (PUFAs) that play crucial roles in various physiological and pathological processes in the body. The term "eicosanoid" is derived from the Greek word "eikosi," meaning "twenty," as these signaling molecules are typically derived from a 20-carbon PUFA, such as arachidonic acid.
Eicosanoids are classified into three major subgroups: prostaglandins, leukotrienes, and thromboxanes. These molecules are synthesized in response to various stimuli, such as inflammation, injury, or infection, and act as potent local hormones or signaling molecules to regulate cellular functions.
Prostaglandins are involved in regulating inflammation, blood flow, and smooth muscle contraction. Leukotrienes are primarily associated with immune and allergic responses, playing a critical role in bronchoconstriction and inflammation. Thromboxanes are involved in platelet aggregation and vasoconstriction, regulating blood clotting and vascular tone.
Eicosanoids exert their effects by binding to specific receptors on target cells, thereby initiating signal transduction pathways and eliciting various physiological responses. Due to their critical role in inflammation and immune responses, eicosanoids have been implicated in various diseases, including asthma, rheumatoid arthritis, cardiovascular diseases, and cancer.
Overall, eicosanoids are a family of lipid mediators that regulate important physiological and pathological processes in the body, making them significant targets for therapeutic interventions in various diseases.
