Mutual relationships between chromogranins A and B and gastrin in individual gastrin cells.

The chromogranins A and B (CgA and CgB, respectively), originally detected in the adrenal medulla, are present in various endocrine organs. Remarkably, their immunoreactivities vary among different endocrine cell types and also within a given endocrine cell population. With densitometric techniques at the cellular level, individual gastrin cells (n = 318) from guinea pig antral mucosa were studied to measure their content of immunoreactive CgA, CgB, and gastrin. The composition of these secretory proteins in individual gastrin cells varied considerably but with predictable components. Statistical evaluation of the data showed that immunoreactivities for gastrin and CgA correlated negatively in these cells; CgA and CgB immunoreactivities also correlated inversely. On the other hand, immunoreactivities for gastrin and CgB exhibited a high positive correlation. The mutual relationships between gastrin, CgA, and CgB suggest that under physiological conditions biosynthetic pathways of these secretory constituents are linked to each other in individual gastrin cells.