Liver Functions/Enzymes

When proteins are altered it can be due to what causes?

liver and kidney disease

What are the most commonly preformed protein assays in vet med?

total protein, albumin, fibrinogen, and globulin

What are some of the function of plasma proteins?

helps form the structural matrix of all cells, organs, and tissues

maintains osmotic pressure, serve as hormones, and functions in blood coagulation

Total protein concentrations can be affected by ________.

altered hepatic synthesis, altered protein distribution, altered protein breakdown/excretion, dehydration, and overhydration

What does Hyperproteinemia mean?

dehydrated (elevated)

What does hypoproteinemia mean?

overhydrated (decreased)

What are the two tests we can use to find out the total protein in our patient?

refractometer and chemistry panel

What does a chemistry panel measure when looking at the total protein?

measures the number of molecules containing more than 3 peptide bonds serum or plasma

Patient should no be losing _____ in the urine.

protein

What percentage does albumin make up od total protein in animals?

makes up 35% to 50% of the total plasma in most animals

Any state of hypoproteinemia is likely cause by _______.

albumin loss

What can albumin levels be influenced by?

renal disase, dietary intake, and intestinal protein absorption

What kind of protein is albumin?

major binding and transport protein

What is Albhumin’s “job” as a protein?

maintains osmotic pressure of plasma

transports bilirubin, ions, fatty acids & drugs

What are some diseases and conditions associated with alteration in serum proteins?

lymphoma, hypoproteinemia / hypoalbuminemia, blood loss, glomerulonephritis, malnutrition, malabsorption, and inflammatory disease

Define alpha globulin.

synthesized in the liver and primarily transport and bind proteins

What do beta globulins do in the body?

responsible for iron transport, heme binding, & fibrin formation/lysis

What are gamma globulin responsible for?

responsible for antibody production (immunity)

Total Protein - Albumin = ________

globulins

An alteration in the albumin/globulin ratio is often the first indication of a _______ ________.

protein abnormality

Albumin/Globulin Ratio is calculated by what?

Calculated by dividing the albumin concentration by the globulin concentration

Albumin/Globulin ratio is usually ____________ in sheeps, horses, goats, and dogs.

greater than 1.0 (Albumin is greater than globulins)

Albumin/Globulin ratio is usually ____________ in cattle, pigs, and cats.

less than 1.0 ( Albumin is equal to or lower than globulins)

Why is fibrinogen not found in serum?

Define fibrinogen

insoluble protein that forms the matrix of blood clots

Fibrinogen makes up ___% to ___% of total plasma proteins.

3% - 6%

What can elevate levels of fibrinogen?

Acute inflammation or tissue damage

In what animals do we see elevated levels of fibrinogen in? What does this mean?

horses, ruminants, and camelids; inflammation

What are acute-phase proteins?

Produced by hepatocytes immediately following injury or inflammation

Albumin & transferrin are ______ acute-phase proteins because _______________________________________________________________.

negative; their plasma concentration decreases following injury or inflammation

What are most acute-phase proteins measured with in domestic animals?

immunoassays

What is the largest internal organ?

liver

What are some of the functions of the hepatobiliary assays?

metabolism of amino acids, carbohydrates, and lipids, digestion and absorption of nutrients, secretion of bilirubin/bile

What is cholestasis?

obstruction of the gallbladder; cannot release bile

How is the gallbladder closely associated with the liver?

both anatomically & functionally

What is the primary function of the liver?

bile storage

What are some malfunctions in the liver/gallbladder?

icterus, hypoalbuminemia, hemostasis problems, hypoglycemia, hyperlipoproteinemia, and hepatoencephalopathy

What enzymes are released from damaged hepatocytes?

alanine transaminase, aspartate transaminase, iditol dehydrogenase, and glutamate dehydrogenase

What enzymes are associated with cholestasis?

alkaline phosphate and gamma glutamyltransferase

What are the two types of hepatocyte function tests?

bilirubin and bile acids

Other hepatocyte function tests are less sensitive & test may not indicate a problem until ⅔ to ¾ of tissue is damaged. What are they?

albumin and cholesterol

What is bilirubin?

Insoluble molecule derived from the breakdown of hemoglobin by macrophages in the spleen

What does bilirubin bind to?

binds to albumin for transport to the liver

What is bilirubin a major component of?

bile

How are urobilinogens broken down/excreted?

are broken down & excreted in feces or may be absorbed in the blood & excreted through the kidney

Unconjugated bilirubin increases with what problems?

liver issues or hemolytic anemia

If there is an increase in conjugated bilirubin, what can this indicate?

bile duct obstruction

What are bile acids?

Synthesized in the hepatic cells from cholesterol & are conjugated with glycine & taurine

What are the functions of bile acids?

aid in fat absorptin and modulate cholesterol levels

Where are bile acids stored?

stored in the gallbladder until contracting associated with feeding

What animal doesnt have a gallbladder?

horses and rats

What are some factors that effect test results with bile acids?

inadequate fasting, food aromas, prolonged fasting, and diarrhea

____% to ___% are actively resorbed in the ileum. Where does the reminder get excreted in?

90% - 95%; remainder is excreted in the feces

postprandial = _____

after eating

What can elevated bile acids indicate?

liver disease - congenital portosystemic shunts, chronic hepatitis, hepatic cirrhosis, cholestasis, and neoplasms

Major source of ALT is the _______.

hepatocyte

Where is ALT found?

in the cytoplasm

What type of test is ALT considered and for what animals?

liver specific test in dogs, cats, and primates

ALT levels can be elevated by what factors?

damage to renal cells, cardiac muscle, skeletal muscle and the pancreas

What does ALT stand for?

Alanine Transaminase

What does AST stand for?

Aspartate Transaminase

Where is AST found?

both in cytoplasm & bound to the mitochondrial membrane

What tissues is AST found in?

RBCs, cardiac muscles, skeletal muscles, kidneys, and pancreas

What does GLDH stand for?

Glutamate Dehydrogenase

What is test is useful in evaluation liver disease in large animals. Is it readily available?

Iditol/Sorbitol Dehydrogenase; not readily available

What animals high concentrations of glutamate dehydrogenase?

cattle, sheep, and goats

What enzymes are associated with cholestasis?

Gamma gultamyltransferase (GGT) and Alkaline Phosphatse (AP or ALK Phos)

What animals have higher GGT’s than dogs and cats?

cattle, horses, sheep, goats, & birds