Early transmission electron micrograph showing intracisternal granules with an electron density equal to that of zymogen granules found in rough endoplasmic the reticulum lumen (cisternae) of animals fed after starvation or after intense in vitro stimulation with secretagogues. Image made available by James D. Jamieson and the Department of Cell Biology, Yale University School of Medicine.
Additional reference: Palade, G.E. 1956. Intracisternal granules in the exocrine cells of the pancreas. J. Biochem. Biophys. Cytol. 2:417-422. Original 3.25 in. x 4 in. lantern slides were scanned at 600dpi. Original Magnification: x13,000