Cyclooxygenase

Definition

Cyclooxygenase (COX) is an enzyme responsible for the formation of prostanoids, including prostaglandins, from arachidonic acid. It plays a key role in inflammatory and pain responses.

5 Must Know Facts For Your Next Test

1. There are two main isoforms of cyclooxygenase: COX-1 and COX-2.
2. COX-1 is constitutively expressed in most tissues, while COX-2 is inducible and often upregulated during inflammation.
3. Nonsteroidal anti-inflammatory drugs (NSAIDs) inhibit cyclooxygenase activity to reduce pain and inflammation.
4. Selective COX-2 inhibitors were developed to minimize gastrointestinal side effects associated with non-selective NSAIDs.
5. Inhibition of COX can lead to reduced production of protective gastric mucosa, potentially causing ulcers.

Review Questions

• What are the two main isoforms of cyclooxygenase and how do they differ?
• How do NSAIDs affect cyclooxygenase activity?
• Why were selective COX-2 inhibitors developed?

Related terms

Prostaglandins:

Lipid compounds that have diverse hormone-like effects, including roles in inflammation and pain.

Arachidonic Acid:

A polyunsaturated fatty acid that serves as a substrate for the synthesis of prostanoids via cyclooxygenase.

NSAIDs:

Nonsteroidal anti-inflammatory drugs that inhibit cyclooxygenase to reduce inflammation, pain, and fever.