Gastrin is a 17 amino acid peptide hormone and neurotransmitter broadly circulated through out the gastrointestinal tract & central nervous system. Antibodies that react particularly with gastrin are useful for the study of differential tissue expression and intracellular and subcellular localization of gastrin in neuroendocrine cells of the gastrointestinal tract， and in the CNS. Antibodies to gastrin can identify and detect gastrin in normal and neoplastic tissue. G cells in the stomach lining produce gastrin. While food enters the stomach， G cells activate the discharge of gastrin in the blood.
When blood levels of gastrin rise， the stomach discharges gastric acid that breaks down and help digest food. Once enough gastric acid has been produced by the stomach， gastrin levels in the blood decrease. Gastrin has slight effects on the pancreas， liver， and intestines. Gastrin helps the pancreas produce enzymes for digestion and helps the liver produce bile. Gastrin stimulates the intestines to help move food through the digestive tract.
