What mechanism do corticosteroids use to decrease arachidonic acid levels from membranes?

Corticosteroids decrease arachidonic acid levels from cell membranes primarily by inactivating phospholipase A2. This enzyme is responsible for releasing arachidonic acid, a key player in the inflammatory response, from membrane phospholipids. By inhibiting phospholipase A2, corticosteroids effectively reduce the availability of arachidonic acid, subsequently leading to decreased formation of pro-inflammatory mediators such as prostaglandins and leukotrienes that are derived from arachidonic acid metabolism.

In the context of inflammation, the reduction of these mediators helps to alleviate the symptoms associated with inflammatory conditions, such as pain and edema. This mechanism is a foundational concept in understanding the anti-inflammatory actions of corticosteroids and underpins their therapeutic use in a variety of inflammatory and autoimmune disorders.