Clinical Significance:
Vasoactive Intestinal Polypeptide (VIP) is a 28 amino acid multifunctional peptide that is involved in gastrointestinal, vasodilator, and neuroendocrine functions. VIP is derived from larger pro-molecules that often exhibit the same or greater immunogenicity than the native VIP. It is structurally related to PHIM, Glucagon, Secretin, Gastric Inhibitory Polypeptide, Corticotropin Releasing Factor and Growth Hormone-Releasing Hormone. VIP stimulates pituitary release of Prolactin, Growth Hormone and ACTH; stimulates Luteinizing Hormone-Releasing Hormone, Serotonin, gastric Somatostatin, Steroids and Renin. VIP inhibits the release of Gastrin, hypothalamic Somatostatin, and Histamine. VIP release is stimulated by cholinergic agonists, Atropine, Serotonin, Prostaglandins E1 and D2, and Nerve Growth Factor. VIP actions are inhibited by Corticosteroids, Dopamine and opiate agonists. Elevated levels of VIP are found in patients with VIPomas, hepatic cirrhosis, and the Verner-Morrison’s (Watery Diarrhea) Syndrome. Decreased levels are found in cystic fibrosis.
Reference Range:
Up to 36 pg/ml
Procedure:
Vasoactive Intestinal Polypeptide is measured by a direct EIA/ELISA.
Patient Preparation:
Patient should be fasting 10 – 12 hours prior to collection of specimen. Patient should not be on any antacid medication or medications that affect intestinal motility for at least 48 hours prior to collection.
Specimen Collection:
Collect 10mL blood in special ISI GI Preservative tube yielding special GI plasma and separate as soon as possible. Freeze plasma immediately after separation. Special G.I. Preservative tubes are available from Inter Science. Minimum specimen size is 1 ml.
Important Precaution:
Vasoactive Intestinal Polypeptide specimens must be collected using the G.I. Preservative. No other specimens are acceptable.
Special Specimens:
For tumor/tissue and various fluids (i.e. CSF, peritoneal, synovial, etc.) contact the Institute for requirements and special handling.
Shipping Instructions:
Ship specimens frozen in dry ice.
References:
1. MS O’Dorisio, CL Wood, and TM O’Dorisio. Vasoactive Intestinal Peptide and Neuropeptide Modulation of the Immune Response. Journal of Immunology 135: 792, 1985.
2. S Ollerenshaw, D Jarvis, A Woolcock. Absence of Immunoreactive Vasoactive Intestinal Polypeptide in Tissue from the Lungs of Patients with Asthma. New England Journal of Medicine 320: 1244, 1989