Measurement of immunoreactive gastrin in tissue

A method for measurement of gastrin in human antral mucosa or in extragastric tissue has been developed and validated. Tissue gastrin was extracted by boiling followed by homogenization at neutral pH. Extractable gastrin immunoreactivity was measured by radioimmunoassay using an antiserum with equal affinity towards G-17 I, G-17 II, G-34 I and G-34 II molecular forms. Almost all extractable gastrin immunoreactivity was recovered after a single extraction and no significant interference by other peptides and/or substances present in tissue was found. The mean gastrin concentration in antral mucosa of healthy subjects was similar to that observed in duodenal ulcer patients, while patients with type A chronic atrophic gastritis or with antral gastrin cell hyperplasia had mean values significantly higher. Gastrin concentration in all specimens from gastrinoma or its metastases was above the upper limit of the range of control tissue. Measurement of tissue gastrin seems to be a valuable tool in the diagnosis of antral gastrin cell hyperplasia and Zollinger-Ellison syndrome.