A stereological analysis of the effect of buffer osmolarity on a salt secreting epithelium, under variable physiological conditions

Abstract

SUMMARY A stereological analysis of salt gland epithelium showed differences in the size of the intracellular space and the volume fraction of some cellular organelles, according to the salinity in which the animals were kept. These changes were similar to earlier non‐quantitative work on several salt secreting epithelia in various states of activity. However, alteration of one variable in the processing technique, osmolarity of the fixative buffer, was shown to produce the same stereological result in salt glands held at constant activity. Most experimental manipulations used in previous experiments to alter glandular activity, e.g. salt loading, altered perfusate, or inclusion of pump inhibitors, probably also alter intracellular ion contents. It is therefore difficult to decide whether changes in lateral intercellular space geometry represent physiological mechanisms in vivo or differences in osmotic behaviour during processing for electron microscopy.