Glutamate Dehydrogenase

Glutamate Dehydrogenase (GLDH) is a mitochondrial enzyme predominantly found in hepatocytes (especially in the centrilobular zone of the liver).
It catalyzes the oxidative deamination of glutamate:

Glutamate + NAD⁺ (or NADP⁺) → α-ketoglutarate + NH₃ + NADH

1️⃣ Marker of Severe Hepatocellular Damage (Very Important)

GLDH is highly concentrated in liver mitochondria.

Markedly Elevated In:

• Acute viral hepatitis
• Toxic liver injury
• Drug-induced hepatitis
• Ischemic liver injury
• Acute liver failure

🔎 Since it is a mitochondrial enzyme, it increases mainly when there is severe hepatocyte necrosis.

2️⃣ Alcoholic Liver Disease

• Alcohol damages mitochondria
• Causes increased GLDH levels
• May help differentiate alcoholic liver injury from mild hepatocellular damage

3️⃣ Differentiation from Other Liver Enzymes

Enzyme Location Significance
ALT Cytoplasm Mild–moderate hepatocyte damage
AST Cytoplasm + Mitochondria Liver & muscle damage
GLDH Mitochondria (Liver-specific) Severe liver necrosis

👉 GLDH is more liver-specific than AST.
👉 Not significantly elevated in muscle diseases.

4️⃣ Not Elevated In

Bone disease

Myocardial infarction

Muscle disorders (minimal rise)

This makes it useful in distinguishing liver damage from muscle injury.

5️⃣ Prognostic Value

High GLDH levels may indicate:

Extensive hepatic necrosis

Poor prognosis in acute liver failure

Normal Reference Range

Approximately 1–10 IU/L
(May vary by laboratory)