Energy dispersive X-ray microanalysis of zymogen granules of mouse pancreas using fresh air dried tissue spread.

Electron microscopy of fresh air dried pancreas spreads revealed a well preserved ultrastructure of pancreatic exocrine cells. The zymogen granules were identified as homogenously electron dense round bodies of approximately 300 nm in diameter, the same as were seen in fresh frozen dried sections. Energy dispersive X-ray microanalysis of zymogen granules and spots 200 nm distant from the granules used as controls disclosed peaks for chlorine, potassium and sulfur in all of five granules examined and in three of them, phosphorus was found in addition to the above elements. The results seem to suggest that pancreatic juice may be contributed from the electrolyte content of secretory granules in contrast to the general assumption that enzymes and electrolytes are separately excreted in pancreatic juice.