11. Pancreatic Function Flashcards
Major source of amylase?
Acinar cells of pancreas
Salivary glands
What is required for functional activation of amylase
Calcium
What is required for FULL activation of amylase
Anions
- bromide
- chloride
- cholate (coenzyme)
- nitrate
2 coupled enzymatic rxns to measure amylase?
- NADH absorption
- Free NP absorption (RXL method)
Why is heparin the only anticoagulant that can be used for amylase samples
Others chelate Ca2+ required for amylase’s functional activation
3 diseases that cause 05% of medical problems associated w/ pancreas?
- Acute pancreatitis
- Chronic pancreatitis
- Pancreatic carcinoma
Common causes of acute pancreatitis
- heavy alcohol use
- intra-abdominal diseases (intestinal obstruction, gallstones blocking common bile duct)
- infections, tumors, trauma
What happens to pancreatic ducts when there’s chronic pancreatitis
Pancreatic ducts calcified, scar tissue builds up = malabsorption
Common causes of chronic pancreatitis
- chronic alcohol abuse
- autoimmune
- genetic mutations due to CF
- blocked pancreatic duct or common bile duct
What happens to AMY levels in chronic pancreatitis (initially, progress)
initially = elevated
declines as acinar tissue destroyed
3 other disorders that can cause elevated AMY?
- Acute appendicitis
- Salivary gland inflammation
- Renal insufficiency
Reference method for lipase measurement?
Titrimetric
Serum and urine amylase levels in acute pancreatitis? (high/low)
Serum = high Urine = high
Serum and urine amylase levels in macroamylasemia? (High/low)
Serum = high Urine = low
What causes macroamylasemia
AMY binding to IgG and IgA = large macromolecule
Can’t be filtered
Amylase: Creatinine Clearance Ratio (ACCR) is used to diagnose what?
Macroamylasemia
Almost all of the lipase
found in serum is derived from the ________
pancreas
What do lipases hydrolyze?
Glycerol esters of triglycerides at ester bond to make glycerol + 3FA
Full activity of lipases requires..?
Cofactors - bile salts (sodium glycocholate) and colipase (coenzyme)
____ is effective in reducing lipase lag phase and activating it
Ca2+
5 rxn methods for analyzing lipase
- titrimetric
- turbidimetric
- spectrophotometric
- fluorometric
- immunological
Why would hemolysis falsely lower lipase results
Hgb inhibits activity of serum lipase
What can falsely increase lipase?
Drugs w/ high conc of free glycerol (colorimetric methods)
2 reasons why elevated lipase cause decrease calcium?
Release of free fatty acids from lipase activity => FAs bind to Ca2+
Liapse needs bile calcium salts as cofactors
What are the 4 types of lipids found in stool?
- Triglycerides (neutral)
- Fatty acid salts (soaps)
- Fatty acids
- Cholesterol
Fecal fat analysis stain?
Oil red O
Sudan III dyes
2 parts of fecal fat stain?
- neutral fat stain
- split fat stain for FAs
3 quantitative methods for fecal fat anaylsis
- gravimetric
- titrimetric
- NMR spectroscopy
Cause of pancreatic malabsorption or insufficiency in children? Adults?
Children - cystic fibrosis
Adults - acute pancreatitis
How does CF affect pancreas
Thick sticky mucous obstructs pancreas passages
4 amylase cofactors
Ca2+
Cl-
Br2+
NO3-
Substrate for amylase
Carbohydrates w/ 1,3-4a-glycosidic linkages (e.g. starch, glycogen)
Levels of amylase and lipase in chronic pancreatitis?
Increase in early stages
Declines as acinar tissue destroyed
Enzyme most specific for acute pancreatitis?
Lipase (>5x RI = acute pancreatitis + rules out other conditions)
