2. Liver

Question 1

liver test for small animals

not useful in ruminants, horse, pigs due to low activity in liver

Answer 1

ALT (Alanine aminotransferase)

Question 2

primary liver enzyme used in large animals

Answer 2

AST (aspartate aminotransferase)

Question 3

SENSITIVE — hepatocellular injury (most spp)
not specific

found in striated muscles & erythrocytes

Answer 3

AST

Question 4

released by leakage or lysis

Answer 4

cytoplasmic isoforms

Question 5

only released by cell lysis

Answer 5

mitochondrial isoform

Question 6

may indicate severe liver injury in dogs & cats

also concurrent hepatic & muscle injury

Answer 6

AST that approaches ALT

Question 7

Half life of AST in canine

Answer 7

12 hours

Question 8

Half life of AST in feline

Answer 8

~1.5 hours

Question 9

Half life of AST in bovine

Answer 9

~2 days

Question 10

Half life of AST in equine

Answer 10

~2 days

Question 11

liver-specific in all species, primarily used in LARGE animals in place of ALT

— in cytosol
— low enzyme stability in vitro hampers use

Answer 11

Sorbitol dehydrogenase (SDH)

Question 12

found in liver & other tissues

NOT specific — hepatocellular injury
little useful information

Answer 12

Lactate dehydrogenase (LDH)

Question 13

a mitochondrial enzyme, liver specific in all species

not widely used

Answer 13

Glutamate dehydrogenase (GLDH)

Question 14

physical obstruction of bile flow that occurs intra/extrahepatic
— hepatic lipidosis
— gallstone

Answer 14

cholestasis

Question 15

enzymes located on the canalicular membrane of hepatocyte and biliary epithelium whose synthesis is induced by cholestasis (and by some drugs)

Answer 15

cholestatic enzymes

Question 16

special assays exist for isoforms;

however, this is only occasionally useful in determining specific cause of increased SAP

Answer 16

enzyme isoforms

Question 17

→ makes up most of SAP in healthy adult animals of most species

→ Activity increases with cholestasis and with certain drugs

Answer 17

liver SAP isoform

Question 18

→ Makes up to 10-30% of total SAP in healthy dogs

→ Increased activity of total SAP within 3-4 days upon exposure to corticosteroids and certain drugs

→ Liver SAP isoenzyme increases first followed by corticosteroid-induced AP isoenzyme in 7 days

only in DOGS

Answer 18

Corticoteroid induced SAP isoform

Question 19

Makes up a small amount of SAP in
healthy adult animals

→ Total SAP is 2-3X higher in young
growing animals
due to the presence of more bone SAP, esp. in horses

→ Increases with bone pathology (~2-4X)
fracture healing
bone tumors
metabolic bone disease

Answer 19

Bone SAP isoform

Question 20

important serum SAP of rodents

Answer 20

Intestinal SAP

Question 21

generally do not appear in serum due to very short half-lives (minutes)

Answer 21

Kidney & Placenta SAP

Question 22

increased delivery of bilirubin to hepatocytes primarily as a result of hemolytic anemia or less often
secondary to massive internal hemorrhage

(e.g., hemoabdomen)

Answer 22

Prehepatic jaudice

Question 23

greater than 50% of bile flow is obstructed

• hepatic lipidosis
• feline cholangiohepatitis

Answer 23

Hepatic jaundice

Question 24

Cause:
- Partial or complete obstruction of bile duct with regurgitation of Bc into circulation and minor reduction in Bu uptake
- Leakage of bile from ruptured gall bladder or bile duct

Examples:
1. gallstones
2. pancreatic abscess/neoplasm regional lymphadenopathy

urine → absence of urobilinogen (in theory)
feces → gray (severe/chronic)

leads to intraheptic disease

Answer 24

Posthepatic jaundice

Question 25

increased immunoglobulins (polyclonal gammaglobulinemia) due to impaired filtering function of liver and escape of antigens to lymphoid tissue

Answer 25

Phagocytic function (Kupffer cells)