Liver enzymes Flashcards
How do we measure proteins?
Purification
Antibodies
Function
What are some enzymes found in the blood?
CAERULOPLASMIN - Ferroxidase
CLOTTING FACTORS - Proteases
Which enzymes are on the liver cell surface
ALP
Which enzymes are in the mitochondria?
Mitochondrial AST
Lysosomal SOD
What marks the destruction of the cell?
Degradation of the cytoskeleton
Swelling
Mallory hyaline
What usually happens in cell death?
It usually blisters in the skin - this then pops open and the bubles can be released into the blood as blebs.
They contain broken down mitochondria
Can the cell survive blebing/blistering?
Yes - it may just be a marker of cell damage
Can repair by removing toxin or restoring oxygen
Questions about enzymes which are detected
Where did they come from (cell)?
How did they get into the blood?
How quickly does the body remove them from the blood?
What are the enzymes in the cytoplasm of the liver cell?
ALT, AST, LD
What are the nucleus in the cytoplasm of the liver cell?
DNA synthase
WHat is seen in liver necrosis
Virus, Toxin, Anoxia
ALT, AST, LD
esp AST with toxins
What is seen in biliary disease
Gallstones, cancer
ALP, GGT
Inducing drugs and what they induce?
Alcohol and anticonvulsants
GGT ALT
ALT
Changes pyruvate to lactate
The anaerobic metabolism of glucose
This occurs in the liver and muscle (mainly in the liver)
AST
Malate shuffle
What happens in hepatitis?
ALT – Cytosol – Liver»_space;> muscle , kidney
AST – Cytosol & Mitochondrial – Liver, Muscle, Blood cells
Source of ALT and AST?
ALT is in the liver
AST is in all mitochondria
What happened if the AST>ALT?
Acute, affecting mitochondria
esp. Acute virus, EtOH
What is going on if ALT>AST?
Chronic / resolving
esp. hepatitis
Drugs, Chronic virus, Metabolic
Some other viral diseases causing hepaiitis?
- EBV (60%)
- CMV (55%)
- Q FEVER (23%)
- RUBELLA (40% (?))
ALT markers?
Normal ALT = 50 MILD ALT=250 MODERATE ALT=1000 SEVERE ALT=5000 (half the liver is dead) ALT of 10000 = going to die
What are acute Hep B ALT levels?
Can be very high even 2500 units
What is a lethal dose of paracetamol?
15g
why would ALT be elevated by AST be normal?
Such a chronic disease that there is not really any significant destruction
What happens in the end stage of cirrhosis?
There is not enough liver to actually damage and release liver enzymes
Where is ALP produced
Bone, Liver, Placenta
Where is GGT produced
Liver, Biliary Epithelium, Renal
What does GGT do?
Adds glutamyl groups to generate GLUTATHIONE
Why is GGT induced by drugs and alcohol?
Tries to produce gluthatione to coutner the toxic effects of these drugs
What does ALP do?
Assists in the transfer across the cell membrane
What causes increased production of bilirubin?
Heamolysis
What causes decreased excretion of bilirubin?
Gilberts, Dubin Johnson, Hepatitis
What happens in extra hepatic cholestasis?
Elevated Conjugated Bilirubin
What happens in intrahepatic cholestasis?
No Jaundice
No increase in Bilirubin
What do high concentrations of bile do in the liver?
High concentrations will degrade the billary membrane
How do GGT and ALP get into the blood stream?
Indirectly via the lymphatics
What happens when NAD+ is depleted?
Glutathione is switched on in order to accommodate for the reduction in NAD+
If GGT is very high what would you expect to see?
ALT would be up - destruction because the cells cannot keep pace with the high levels of toxins
Relationship between liver obstruction and hepatocellular death?
HEPATOCELLULAR DEATH – Death of liver cells – Inflammation & swelling –Biliary Obstruction
BILIARY OBSTRUCTION – Inability to excrete toxins – Accumulation of toxins in hepatocyte –Hepatocellular death
What happens to fructose?
The liver can convert it to glucose but instead it converts it to fat
What is the cause of fatty liver?
Sugar consumption = high fructose levels = conversion to fat
