VIP is recognised as a neurotransmitter and neuroendocrine modulator present in the digestive, cardiovascular, respiratory, central and peripheral nervous systems. Due to the widespread distribution of VIP, it is thought it contributes to a number of pathological and physiological processes relating to growth, development and neuronal and endocrine cell functions.
Within the gastrointestinal tract, VIP mediates a number of cellular functions, some of which include regulation of smooth muscle, vasodilation, stimulation of water and bicarbonate secretion. It is believed to have a crucial role in the regulation of intestinal motility, and epithelial ion and water transport.
VIP testing is indicated in the investigation of severe, watery diarrhoea, or WDHA (watery diarrhoea, hypokalaemia, achlorhydria) syndrome. Over secretion of VIP is characteristic of a vasoactive intestinal polypeptide-producing tumour (VIPoma).
As VIPomas may secrete VIP intermittently, it is recommended to take samples during a symptomatic episode.
Endo/Steroid Lab
VIP
Sample should be sent on ice to laboratory asap.
Centrifuge at 4 oC and freeze plasma within 1 hour of collection.
Avoid repeat freezing and thawing.
No
VIP
6 weeks
6520