Cytoplasmic crystalline aggregates in murine pancreatic acinocytes

Crystalline inclusions were regularly observed in the cytoplasm of about 10% of pancreatic acinocytes of adult mice. Such structures were never found in ductular or islet cells. The crystals were usually rectangular, lay in the basal region of the cell in the hyaloplasm between adjacent lamellae of endoplasmic reticulum, and were composed of parallel, dense lines 60–70 A° in thickness separated by less dense interspaces 90-100 A° in width.