What are pancreatic enzymes?
Pancreatic enzymes are digestive enzymes produced by the pancreas. Each day, the organ produces one to two liters of digestive juice, which flows through the main duct (ductus pancreaticus) into the duodenum – the first section of the small intestine. The following pancreatic enzymes are contained in the pancreatic juice:
- enzymes that cleave carbohydrates (alpha-amylase, glucosidases)
- enzymes that break down fat (lipase, phospholipase A and B, cholesterol esterase)
- enzymes that cleave proteins (trypsin, chymotrypsin, elastase, collagenase, kallikrein, carboxypeptidase)
Most pancreatic enzymes are secreted by the pancreas as precursors, as so-called zymogens: trypsinogen, chrymotrypsinogen, procarboxypeptidases, and prophospholipase A. They are only converted into their effective form in the small intestine, where they participate in the digestion of the ingested food.
How many pancreatic enzymes are released is regulated on the one hand by the vagus nerve and on the other hand by hormones. These are hormones that are produced in the intestinal cells or in the so-called islet cells of the pancreas. For example, the hormone cholecystokinin (= pancreocymin) stimulates the release of pancreatic enzymes.
When do you determine pancreatic enzymes?
Of the various pancreatic enzymes, amylase and lipase are considered lead enzymes. They can be determined via a blood sample. For cost reasons, both pancreatic enzymes are often not determined at the same time. Lipase is usually measured because it remains elevated longer than amylase and many patients do not go to the doctor right at the onset of a disease.
Amylase
The amylase in the urine increases with a time lag. However, due to the poorer hit rate, the urine test is hardly used anymore.
Lipase
The enzyme lipase in the body originates predominantly from the so-called acinar cells of the pancreas. In the blood, lipase increases within four to eight hours after the onset of the disease and decreases again within 8 to 14 days. It thus remains elevated longer than amylase.
Pancreatic enzymes: reference values
The amylase concentration is not measured in its absolute amount, but in enzyme activity units (U) per liter of substrate (blood serum, spontaneous urine, collected urine). In the following table you will find the reference values for adults:
|
Normal values |
Pancreatic amylase (measurement at 37°C) |
|
Serum |
< 100 U/l |
|
Spontaneous urine |
< 460 U/l |
|
Collect urine |
< 270 U/l |
Depending on the measuring method used, the reference values may differ, therefore only guide values can be given here.
|
Pancreatic Lipase |
|
|
Adults |
13 – 60 U/l |
|
Children |
up to 40 U/l |
When are pancreatic enzymes low?
In the case of chronic inflammation of the pancreas (chronic pancreatitis) and pancreatic cancer, the gland may no longer produce sufficient digestive enzymes. The measured values for pancreatic enzymes are then reduced. Doctors refer to this as exocrine pancreatic insufficiency.
When are pancreatic enzymes elevated?
Other important causes of elevated pancreatic enzymes include:
- benign and malignant pancreatic tumors
- pseudocysts or ductal stenosis (strictures) following acute pancreatitis
- Other diseases involving the pancreas such as gastrointestinal perforation, intestinal obstruction (illeus), mesenteric infarction
- Medications such as azathioprine, 6-mercaptopurine, mesalazine, the “pill,” opiates, or antibiotics; increased pancreatic lipase due to anticoagulants (such as heparin)
If a patient has low pancreatic enzymes (and thus exocrine pancreatic insufficiency), the cause must be clarified. The physician then usually determines the amount of elastase in the stool and performs a special test (secretin-pancreozymin test).
In the case of elevated pancreatic enzyme levels, the physician will carefully take the patient’s medical history, especially with regard to digestive complaints, previous illnesses and medication use. This is followed by a physical examination and further investigations and laboratory tests to clarify possible causes.
Once the cause of the altered blood levels of pancreatic enzymes has been determined, the physician will initiate appropriate treatment.
