Clinical Significance:
Vasoactive Intestinal Polypeptide (VIP) is a 28 amino acid multifunctional peptide that is involved in gastrointestinal, vasodilator, and neuroendocrine functions. 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 inhibitis 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 watery diarrhea syndrome. Decreased levels are found in cystic fibrosis. VIP is excreted into the urine which allows a 24 hour integrated picture of VIP release.
Reference Range:
Up to 70 ng/24 hours
Procedure:
Urine 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:
10 ml of a 24 hour urine collection should be submitted for analysis. No special preservatives are required. Store specimen refrigerated during collection. Specimens should be frozen prior to shipping. Minimum specimen size is 5 ml.
Shipping Instructions:
Ship specimens frozen in dry ice. Provide the total volume per 24 hours.
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.