Cyclooxygenase

Cyclooxygenase (COX) is an enzyme that is responsible for the formation of important biological mediators called prostaglandins, which are involved in inflammation and other critical physiological functions. There are two main isoforms of cyclooxygenase: COX-1 and COX-2.

Function

Cyclooxygenase enzymes catalyze the conversion of arachidonic acid to prostaglandin H2 (PGH2), the precursor of other prostaglandins, prostacyclin, and thromboxane. These compounds are involved in various physiological processes, including the regulation of inflammation, pain, and fever.

Isoforms

COX-1

COX-1 is constitutively expressed in most tissues and is involved in the regulation of normal cellular processes, such as the protection of the gastric mucosa, platelet aggregation, and maintenance of renal blood flow.

COX-2

COX-2 is an inducible enzyme that is expressed in response to inflammatory stimuli, such as cytokines, growth factors, and tumor promoters. It is primarily involved in the inflammatory response and is a target for nonsteroidal anti-inflammatory drugs (NSAIDs).

Inhibition

Cyclooxygenase inhibitors, such as aspirin and other NSAIDs, work by blocking the activity of COX enzymes, thereby reducing the production of prostaglandins and alleviating symptoms of inflammation and pain. Selective COX-2 inhibitors, also known as coxibs, were developed to reduce gastrointestinal side effects associated with traditional NSAIDs.

Clinical significance

The inhibition of COX enzymes has therapeutic benefits in the treatment of conditions such as arthritis, menstrual pain, and cardiovascular disease. However, long-term use of COX inhibitors can lead to adverse effects, including gastrointestinal bleeding, renal impairment, and increased risk of cardiovascular events.

See also

• Prostaglandin synthesis
• Nonsteroidal anti-inflammatory drug
• Arachidonic acid

External links

• Cyclooxygenase on WikiMD