Morphologic heterogeneity of mouse Paneth cell granules before and after secretory stimulation.

Abstract

AbstractPaneth cells from fasted, fed and pilocarpine stimulated mice were studied with the light and electron microscopes. While human and rat Paneth cells contain structurally homogeneous granules, most mouse Paneth cell granules were found to be structurally heterogeneous both by light and electron microscopy. These structurally heterogeneous granules consisted of an outer rim or halo which surrounded the central core of the granule. These halos varied strikingly in electron density ranging from much paler to much darker than the granule core. Electron density of the halos correlated well with their affinity for toluidine blue in light microscopic preparations. The granule halo could be stained with both alcian blue and with PAS indicating that it contained acid mucopolysaccharide while the central core of the granule could be stained only with PAS and not with alcian blue.While actively secreting Paneth cells were seen in preparations from fasting mice, the secretory activity was increased after feeding and after stimulation with pilocarpine. The actively secreting mouse Paneth cells discharged their granules into the crypt lumen by merocrine secretion. The fine structure of mouse Paneth cell granules was the same in resting and in actively secreting cells.