VIP levels are extraordinarily high in:
VIP belongs to the family of secretin and glucagon. VIP is usually produced by neurons. So its levels are kept minimum in blood normally. But in pancreatic cholera (Verner morrison syndrome) VIP levels are extraordinarily high in serum. It leads to watery diarrhea, hypokalemia, achlorhydria. Ref: Sleisenger and Fordtran's, Edition-9, Page-7
Verner-morrison syndrome
Celiac disease
Zollinger ellison syndrome
Paraganglioma