The enzyme gamma-glutamyl transferase (GGT) is found in many organs throughout the body, with the highest concentrations in the liver. The primary function of GGT is the breakdown and recycling of glutathione, which is the most important antioxidant in the human body. GGT levels in the blood are elevated when there is potential liver or bile duct damage or high glutathione use in the body and oxidative stress.
GGT is also involved in:
* Breaking down drugs and toxins
* Forming amino acids important for the brain and heart (gamma-glutamyl-taurine to taurine)
* Transforming inflammatory molecules
GGT may leak into your bloodstream if your liver or bile duct is damaged, so having higher levels of GGT in your blood may indicate damage to your liver’s bile ducts. GGT is typically the first liver enzyme to increase in your blood when any of your liver bile ducts become blocked or constricted. Because of this, it’s the most sensitive liver enzyme test for finding bile duct issues.
Your GGT levels can also rise from administration of foreign substances such as medications (like phenobarbital, phenytoin or warfarin) or alcohol.