Question

What is the relationship of prostaglandins, leukotrienes, and thromboxanes with any form of lipids?

Answer 1

All these prostaglandins, thromboxanes and leukotrienes are synthesized from one polyunsaturated fatty acid Arachidonic acid.

These all are chemical derivatives of eicosanoids.

Eicosanoids (Eicosa means 20) are nothing but oxygenated derivative of 20 carbon unsaturated fatty acids like arachidonic acid

Prostaglandins are produced by more or less every tissue in humans. Their synthesis from arachidonic acid happens by cyclooxygenase pathway. The key enzymes are cyclooxygenases (COX 1 and COX 2). Cyclooxygenases produce endoperoxides which are latter converted into either prostaglandins or thromboxanes.

Several inhibitors of cyclooxygenases like aspirin have been used to reduce prostaglandin synthesis and hence inflammation. Prostaglandins are powerful vasodilators and cause inflammation.

Leukotrienes are another class of derivatives of eicosanoid. They are produced by macrophages and leukocytes. They are made by lipoxygenase pathway. .

Initially 15 lipoxygenase converts arachidonic acid to hydroperoxides. Hydroperoxides are latter converted to leukotrienes by the action of 5 lipoxygenase Leukotrienes play a significant role in asthma. It acts as vasoconstricter.

Therefore, all these prostaglandins, thromboxanes and leukotrienes are synthesized from one polyunsaturated fatty acid Arachidonic acid.