Definition of Vasoactive intestinal polypeptide:

Vasoactive intestinal polypeptide (VIP) is a substance found throughout the body. The highest levels are normally found in the nervous system and gut. VIP has many functions:

• It helps control or send nerve signals
• It helps relax certain muscles along the gastrointestinal tract
• It increases the amount of water and electrolytes released from the pancreas and gut
• It triggers the release of hormones from the pancreas, gut, and hypothalamus
• It helps break down fat and glycogen
• It stimulates bile flow
• It blocks gastrin and gastric acid release

A blood test can be done to find out how much VIP you have in your blood.

How the test is performed:

A blood sample is needed. For information on how this is done, see: Venipuncture.

How to prepare for the test:

You should not eat or drink anything for 4 hours before the test.

How the test will feel:

When the needle is inserted to draw blood, some people feel moderate pain, while others feel only a prick or stinging sensation. Afterward, there may be some throbbing.

Why the test is performed:

This test is used to confirm the presence of a VIPoma, a tumor that releases VIP.