The document discusses pancreatic digestive enzymes including amylase and lipase. It notes that amylase breaks down starches into smaller units and is produced in the pancreas and salivary glands. Elevated amylase levels can indicate acute pancreatitis or other conditions. Lipase breaks down fats and is also produced primarily in the pancreas. Lipase levels are more specific for pancreatic disorders than amylase and remain elevated longer in acute pancreatitis. Both enzymes can be measured using colorimetric or other laboratory methods.
1. Digestive enzymes of pancreatic
origin
Exocrine secretions
Alkaline bile,bicarbonate rich fluid containing
various enzymes for normal digestion
Proenzymes forms of proteases
Trypsin
Chymotrypsin
Carboxypeptidase
Lipase
amylase
2.
3. Digestive enzymes of pancreatic
origin
Amylase
Belonging to class of hydrolases that catalyze
the breakdown of starch and glycogen.
Imp enzyme in physiological digestion of
starches.
Cellulose and other structural polysaccride
consisting of linkages are not attacked by
amylase.
7. Tissue source of amylase
Acinar cells of pancreas ( pancreatic AMY)
Salivary glands major source of serum amylase
Smallest enzyme 50000-55000
Also filtered by glomerular and appears in urine.
Digestion of starches begins in mouth Salivary
amylase hydolytic reaction
Pancreatic AMY perform major digestive action
on starch once polysaccrides reach the intestine.
8. Diagnostic significance
Elevated amylase levels
Acute pancreatitis
5 to 8 hrs after onset of attack, peak at 24 hrs
return to normal 3 to 5 days.
salivary gland lesions e.g: Mumps, parotitis,
other intra abdominal diseases perforated peptic
ulcer, intestinal obstruction,choleystitis mesenteric
infarction, acute appendicitis.
9. Methods of determination
1.Amyloclastic
Amylase in serum is allowed to act on substrate
starch+iodine added
As amylase hydrolyzes starch molecule into
smaller units the iodine is release and a decrease
in initial dark blue color intensity of starch iodine
complex
The decrease in color is proportional to AMS
conc.
10. 2.Saccharogenic method
Classic reference method
Starch substrate hydrolyzed by the action of AMS
into reducing sugars maltose isomaltose
The amount of reducing sugars is measured
where the concentration is proportional to AMS
activity.
11. 3.Chromogenic methods
Starch substrate to which chromogenic dye have
been attached forming insoluble substrate
complex.
As AMS hydrolyzes the starch substrate smaller
dye substrate fragments are produced these are
water soluble
The increase in color intensity is proportional to
AMY active.
12. Measurement of serum amylase
.4.Coupled enzyme assays have been used
AMY activity by a continuous monitoring
technique in which change of absorbance of NAD
at 340 nm is measured.
Reference range
In serum 28-100U/L
In urine 1-15 U/h
14. Sources of error
AMY in serum and urine stable
Little loss of activity at room temperature for 1 week
or at
4⁰ C for 2 months
Because TG suppress or inhibit serum AMY
activity,AMY values may be normal in acute
pancreatitis with hyperlipaema.
Falsely elevated levels caused by drugs morphine for
pain relief before sampling .
The drugs cause consctriction of sphincter of oddi and
of pancreatic ducts thus increase in interculate
pressure causing regurgitation of AMY into serum.
15. Hyperamylasemia
Asymptomatic condition
Can occur in neoplastic diseases upto 50 times
high ULN.
Macroamylasemia when AMY molecule combine
with immunoglobulins form a complex too large to
filtered through glomerulus.
Serum AMY level rise
Urinary AMY abnormally low
16. Isoenzymes
In normal human serum two major bands. The
bands are p-type and S-type Isoenzymes of
salivary origin (S1,S2,S3)
The isoenzymes of salivary origin moves quickly
as compared to p type.
Pancreatic origin (P1,P2,P3)
Most commonly P2,S1,S2
Acute pancreatitis increase in P-type with p3
most predominanat.
18. Lipase (LPS)
Hydrolyzes the ester linkages of fats to produce
alcohols and fatty acids.
LPS catalyzes the partial hydrolysis of dietary TG
in intestine to 2-monoglyceride and fatty acids.
19.
20. Tissue source:
LPS found primarily in pancreas, stomach and
small intestine.
21. Diagnostic significance
Diagnosis of acute pancreatitis LPS levels
Serum lipase activity increase 4-8hr after an
attack
It is considered more specific for pancreatic
disorders than AMY .
LPS elevations persist for only 8days in acute
pancreatitis where as AMY for only 2-3 days.
In contrast to Amy levels serum LPS are normal
in conditions of salivary gland involvement.
Therefore LPS levels are useful in differentiating
serum AMY elevation as a result of pancreatic
versus salivary involvement
23. In laboratory
Colorimetric methods are also available based on
coupled enzyme assays.or LPS turbidimetric
methods
Triglceride + 2H2O 2-monoglceride + 2
fatty acids
Reference range
< 38 U/L