Gastrin I, human, is primarily utilized in medical and biological research to study its role in the digestive system. It is often employed in experiments to understand its effects on gastric acid secretion, which is crucial for digestion. Researchers use it to investigate conditions related to hypergastrinemia, such as Zollinger-Ellison syndrome, and to explore its impact on the growth of gastrointestinal cells. Additionally, it serves as a tool in pharmacological studies to develop and test drugs targeting gastrin receptors, aiming to treat disorders like peptic ulcers and certain types of stomach cancers. Its application extends to in vitro and in vivo models to elucidate its physiological and pathological mechanisms.