Human peptide histidine-methionine (PHM) is a 27-amino-acid peptide belonging to the glucagon-secretin family of peptide hormones. PHM is produced from the same prohormone as VIP, with which it shows considerable sequence homology. The VIP/PHM prohormone is produced by neurons in the central and peripheral nervous systems, often together with acetylcholine. In some situations the effect of the peptides is to reinforce and prolong the effects of neurotransmitter release. Like VIP,PorcineHM is a vasodilator and stimulator of intestinal fluid secretion. High plasma levels of PHM are diagnostic of the corresponding peptide-producing tumor (VIPoma), associated with the watery diarrhea-hypokalemia-achlorhydria syndrome. This antibody binds human PHM and cross-reacts with PACAP (appro, Xenopus/Amphibian,imately 12%, incomplete non-parallel inhibition). This antibody does not cross-react with GLP-1, GLP-2, VIP or glucagon.