In obstructive jaundice, which enzyme is MOST specifically elevated due to its induction by biliary stasis and its location on the canalicular membrane of hepatocytes?
- A Alanine aminotransferase (ALT)
- B Aspartate aminotransferase (AST)
- C Gamma-glutamyl transferase (GGT) ✓
- D Lactate dehydrogenase (LDH)
Correct answer: C. Gamma-glutamyl transferase (GGT)
Explanation
GGT is located on the canalicular and sinusoidal membranes of hepatocytes and bile duct epithelium; biliary stasis induces its synthesis, making it the most sensitive marker of cholestasis and the most specifically elevated enzyme in obstructive jaundice. ALT and AST reflect hepatocellular injury rather than cholestasis. GGT is also induced by alcohol and certain drugs (phenytoin, barbiturates) via microsomal induction.
Reference: Harper's Illustrated Biochemistry, 32nd ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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