Control of secretory granule interaction and exocytosis in pancreatic cells.

Application of the laser-based technique of photon correlation spectroscopy to an in vitro study of the ionic stability and interaction kinetics of zymogen granules isolated from rat exocrine pancreas is described here. In addition the separation from pancreatic acinar cell cytosol of a factor which stabilizes isolated zymogen granules and inhibits cation-induced granule aggregation is outlined. The basis of this action and the significance of the cytosolic inhibitory factor in the regulation of granule mobility and exocytosis in vivo is discussed.