Ionic components of secretory cell surfaces in relation to secretory function.

Abstract

Rat pancreas was examined by ultrastructural cytochemical methods for localizing cations and anions, as well as polyanions and, more specifically, sulphated mucosubstance. Exceptionally abundant antimonate-precipitable cation was demonstrated between pancreatic acinar cells and at the base of the centro-acinar and other duct epithelial cells. Precipitates of nuclear heterochromatin appeared lighter whereas those of mitochondria and cytoplasm were coarser and more conspicuous in acinar that duct cells. Stimulation with synthetic secretin at a low level diminished antimonate reactivity of nuclei as well as the precipitation at the basement membrane of centro-acinar cells. At a higher dose, secretin selectively eliminated precipitation between and below centro-acinar and other duct cells while inducing increased antimonate-reactive cation in centro-acinar cells and the acinar lumens. Pancreozymin stimulation elimated antimonate-precipitable cations between acinar cells and, to a much lesser extent, those between duct cells and increased cytoplasmic precipitates on granular reticulum of acinar cells.