Liver EnZ Tests Flashcards
Any condition in which the flow of bile from the liver is inhibited
or blocked
Cholestasis
Causes of Extrahepatic cholestasis (occurs outside the liver)
Strictures (narrowing of bile duct)
Stones in common bile duct
Pancreatitis
Primary sclerosing cholangitis (inflammation & scarring of bile duct)
Cysts
Tumors (bile duct; nearby tumors which exert pressure on bile duct
Causes of Intrahepatic cholestasis (occurs inside the liver)
Alcoholic liver disease
Primary biliary cirrhosis
Viral hepatitis
Medications responsible for cholestasis
Antibiotics (e.g., penicillins)
Anaboic steroids
Birth control pills
ALP (alkaline phosphatase), 5’NT and GGT are all test for what and located where?
cholestasis adn are on teh cell membrane; associated with biliary type disease
AST & ALT catabolize “glucogenic” amino acids such as
aspartate and alanine
AST Aspartate aminotransferase
= SGOT, serum glutamic oxaloacetic transaminase
Two isoforms:
GOT1 =________ form
GOT2 =________ form
cytoplasmic
mitochondrial
Both isoforms of GOT require________ as a cofactor
Broad tissue distribution: liver, cardiac muscle, skeletal
muscle, kidney, brain, pancreas, lung, leukocytes,
erythrocytes (liver highest, erythrocytes lowest)
pyridoxal phosphate (PLP)
~80% of AST activity in human liver is due to ________ form
GOT2 mitochondrial
AST (SGOT) take L-aspartic acid and ketoglutaric acid to:
L-glutamic acid and oxaloacetic acid
ALT Alanine aminotransferase
= SGPT, serum glutamic pyruvic transaminase
Present only in the_____
Requires ________ as a cofactor
Tissue distribution: found predominantly in the_____
cytoplasm
pyridoxal phosphate (PLP)
liver
Aminotransferases ALT/SGPT takes alanine and alpha-ketaglutaric acid to:
to L-glutamic and pyruvic acid
AST & ALT are not exclusively expressed in the liver.
However,_____ is predominantly expressed in liver. Therefore,
is a more specific test of acute hepatocellular damage
ALT
Elevated AST & ALT are NOT specific for_______
They are also found in patients with severe cardiac and skeletal
muscle damage.____ is more often increased in patients with
myocardial infarction
hepatobiliary disorders.
AST
Liver Cell Necrosis
ALT > AST____ hepatitis
AST > ALT____ hepatitis
viral
alcoholic
Membrane-bound metalloenzyme which catalyzes the
hydrolysis of phosphomonoesters at an alkaline pH
ALP Alkaline phosphatase
Elevated serum ALP observed in disorders of _____
characterized by increased_____ activity, and as
normally occurs during growth and pregnancy
bone
osteoblastic
Involved in purine catabolism. Catalyzes hydrolysis of
nucleotides such as adenosine 5’-phosphate in which the
phosphate is attached to the 5 position of the pentose ring
5’NT 5’-Nucleotidase
5’NT 5’-Nucleotidase: Broad tissue distribution: liver, intestines, brain, heart, blood
vessels, pancreas.
In liver, enzyme is associated primarily with
canalicular
and sinusoidal plasma membranes.
In contrast to alkaline phosphatase, ________is not
elevated in bone disease or during pregnancy.
5’-nucleotidase
Catalyzes the transfer of the γ-glutamyl group from γ-glutamylcontaining
peptides such as glutathione to other peptides, amino
acids, or water.
GGT γ-Glutamyl Transpeptidase
When is GGT levels elevated?
GGT is frequently elevated in diseases of liver, biliary tract, and pancreas.
Certain medications (barbiturates, anticonvulsant drugs) and alcohol abuse (i.e.,
increases hepatic microsomal GGT) can cause elevated serum GGT levels
Unlike alkaline phosphatase,___ is NOT elevated in bone disease.
GGT
TRANSAMINASES:
ALT (SGPT) & AST (SGOT)
• Both located in the_____
–____ in cytoplasm + mitochondria
–____ in cytoplasm
• Elevation usually indicates hepatocyte (liver
cell) injury
hepatocytes
AST
ALT
• An enzyme on the surface of the liver cells that is adjacent
to the bile canaliculi
• Usually elevated with biliary obstruction or cholestatic
process
• Present in
– Liver
– Bone
– Intestine
– Placenta
Alkaline Phosphate
If Alk Phos is elevated, what other levels can you check to be sure of hepatic origin?
Isoenzymes
– 5̕ -nucleotidase
– GGT
• The product of red blood cell breakdown
• First produced as water-insoluble
(unconjugated/indirect)
Bilirubin
Liver cells conjugate indirect bilurubin through
the action of ________ and
make it water soluble (conjugated/direct)
allowing it to be secreted in bile
UDP-glucuronyltransferase
Increased direct (conjugated) bilirubin resluts in:
– Liver injury
– Bile duct problems
– Rare metabolic problems
• Increased indirect (unconjugated) bilirubin results in
– Hemolysis
– Gilbert’s
- Both are good indicators of liver synthetic function
- Both can be affected by poor oral intake and severe infections
ALBUMIN AND INR
• Replacement of vitamin K corrects the INR if due to _______ but not if due to
________
• Proteinuria and GI loss can decrease_______levels
nutritional causes
hepatic dysfunction
albumin
• Hepatocellular: (ALT/AST) list of diseases
– alcohol
– viral hepatitis
– autoimmune hepatitis
– hemochromatosis
– Wilson’s Disease
– fatty liver
– alpha-1 antitrypsin
deficiency
– medications
List of • Cholestatic/Obstructive:
(alkaline phosphatase)
– stones
– primary biliary cirrhosis
(PBC)
– primary sclerosing
cholangitis (PSC)
– medications
Infiltrative liver disease:
- Space occupying lesion
- __________elevation
- Occasional bilirubin elevation
- Examples: tumors, amyloid, sarcoid
Alkaline phosphatase
Why is Bilirubin frequently not helpful in determining type of injury
– Can become elevated due to hepatic as well as nonhepatic causes
– Can become elevated in hepatocellular, cholestatic as well as infiltrative disease
• ALT > 500 =
Hepatitis A, Hepatitis B,
autoimmune hepatitis, medications, ischemia
(shock liver), rarely stone passage
• Alcoholic liver disease rarely has transaminases
>300
• AST:ALT > 2:1 is suggestive of
alcoholic liver disease
- ALT 614
- AST 567
- ALK PHOS 145
- TOTAL BILI 10.3
- DIRECT BILI 7.6
- INR 1.2
Pt has hepatocellular injury with normal alk phos
the elevated TOTAL bili means they are jaundice
the INR is normal thus they are compensated
