Liver Enzymes: ALT and AST

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Questions and Answers

What is the primary difference between ALT and AST in terms of their presence in the body?

ALT is found in the brain and red blood cells, while AST is found in the liver and kidneys

ALT is found predominantly in the liver, with negligible quantities found in other organs (correct)

AST is found only in the liver, while ALT is found in the heart and skeletal muscle

ALT is found in the liver and kidneys, while AST is found in the heart and skeletal muscle

What is the typical pattern of AST elevation in myocardial infarction?

AST increases gradually over several days and returns to normal after 1 week

AST increases immediately after onset of infarction and returns to normal within 1 hour

AST does not increase in myocardial infarction

AST increases 4-6 hours after onset of infarction, peaks 16-48 hours, and returns to normal 3-5 days later (correct)

Which of the following conditions is associated with an elevation of only AST?

Fatty liver

Autoimmune hepatitis

Hepatocellular carcinoma

Myocardial infarction (correct)

What is the primary function of alkaline phosphatase (ALP) in the liver?

To remove phosphate groups from molecules Signup and view all the answers

Which of the following conditions is associated with an elevation of both ALT and AST?

Acute liver viral infections Signup and view all the answers

What is the primary site of alkaline phosphatase (ALP) in the liver?

Biliary ducts Signup and view all the answers

Which of the following medications is associated with an elevation of ALT and AST?

All of the above Signup and view all the answers

What is the characteristic of AST elevation in skeletal muscle disease?

AST increases moderately and persists for a longer duration than CK Signup and view all the answers

What is the effect of alcohol on GGT production?

It increases GGT production by inducing hepatic microsomal production Signup and view all the answers

In what percentage of chronic drinkers is GGT level elevated?

75% Signup and view all the answers

In which of the following conditions is GGT elevated?

Alcoholic liver disease Signup and view all the answers

What is the primary cause of GGT elevation in toxic hepatitis?

Stimulation of excess proteins synthesis Signup and view all the answers

What is the main value of GGT over ALP in diagnosing biliary disease?

GGT is better in verifying that ALP elevations are due to biliary disease Signup and view all the answers

What is the primary function of GGT in glutathione metabolism?

Transferring gamma-glutamyl moiety to form glutamate Signup and view all the answers

What is the primary function of albumin in the body?

To maintain vascular volume by preventing movement of fluid from the intravascular to the extravascular space Signup and view all the answers

Which of the following is NOT a cause of elevated ALP levels?

Malnutrition Signup and view all the answers

What is the role of GGT in the liver?

Transferring gamma-glutamyl functional groups Signup and view all the answers

Where is albumin synthesized in the body?

Liver Signup and view all the answers

What is the effect of GGT elevation in pancreatic disease?

It is moderately elevated in acute pancreatitis Signup and view all the answers

Which of the following enzymes is elevated in liver disease?

All of the above Signup and view all the answers

What is the correlation between GGT and ALP in detecting biliary disease?

They are positively correlated Signup and view all the answers

What is the location of GGT in the liver cell?

Cell membrane Signup and view all the answers

Which of the following is a cause of decreased ALP levels?

Cretinism Signup and view all the answers

What is the relationship between GGT and glutathione metabolism?

GGT is involved in glutathione metabolism by transferring gamma-glutamyl moieties Signup and view all the answers

Study Notes

Liver Enzymes (SGPT & SGOT)

ALT is found predominantly in the liver, with clinically negligible quantities found in kidneys, heart, and skeletal muscle.
AST is found in the liver, heart, skeletal muscle, kidneys, brain, and red blood cells.
ALT is a more specific indicator of liver damage than AST.
Elevation of only GOT (AST) is seen in:
- Myocardial infarction (increases 4-6h after onset, peaks 16-48h, and returns to normal 3-5 days later)
- Skeletal muscle disease (e.g., Duchenne muscular dystrophy)
- Hemolytic anemia (e.g., sickle cell anemia)
Elevation of both ALT and AST is seen in:
- Acute and chronic liver viral infections (e.g., HAV, HCV, HBV)
- Fatty liver (alcohol related and non-alcohol related conditions)
- Hepatocellular carcinoma (HCC)
- Autoimmune hepatitis
- Some medications (e.g., certain antibiotics, statins, and fenofibrate)
- Hemochromatosis and Wilson disease
- Hypothyroidism

Alkaline Phosphatase (ALP)

Sites: ALP is found in cells lining the biliary ducts of the liver, bone, intestine, and placental tissue.
Functions: responsible for removing phosphate groups from molecules, including nucleotides and proteins, through dephosphorylation.
Elevated ALP levels can be caused by:
- Bone diseases (e.g., Paget's disease, osteosarcoma, bone metastases of prostatic cancer, fractured bone)
- Cholestasis-causing drugs (e.g., antidepressants, immunosuppressants)
- Hepatotoxicity-causing drugs (e.g., paracetamol, antiepileptic)
Decreased ALP levels can be caused by:
- Malnutrition
- Cretinism (hypothyroidism in infancy)
- Congenital hypophosphatasia (rare inherited disorder)

Gamma Glutamyl Transferase (ɣ-GT)

Sites: ɣ-GT is found in many tissues, with the liver being the most notable one.
Functions: involved in glutathione metabolism, transferring gamma-glutamyl functional groups to various acceptor molecules.
Elevated serum ɣ-GT activity can be found in diseases of the liver, biliary system, and pancreas, including:
- Liver disease (e.g., acute hepatitis, alcoholic liver disease, hepatic malignancies)
- Biliary disease (e.g., intra and extra hepatic cholestasis)
- Pancreatic disease (e.g., acute pancreatitis, pancreatic malignancy with hepatobiliary obstruction)

Albumin

Albumin is the most abundant protein in human blood plasma, produced in the liver.
Albumin creates 75-80% of plasma colloid oncotic pressure, maintaining vascular volume by preventing fluid movement from the intravascular to the extravascular space.
Albumin functions include:
- Maintaining vascular volume
- Preventing movement of fluid from the intravascular to the extravascular space

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Description

This quiz focuses on the difference between Alanine Transaminase (ALT) and Aspartate Transaminase (AST) in the human body, particularly in relation to liver damage and other organs.