LOCALIZATION OF ACID PHOSPHATASE ACTIVITY IN RAT PANCREATIC ACINAR CELLS: A LIGHT AND ELECTRON MICROSCOPIC STUDY

Abstract

Small blocks of pancreas from Holtzman and Fischer -strain male rats weighing 150-350 gm were fixed in cold formol-calcium for 24 hours or 6.25% glutaraldehyde for 2 hours followed by a wash in cold buffer for 24 hours. Free floating 10u sections were incubated in the Gomori acid phosphatase medium with B-glycero-phosphate as substrate for light microscopy and 40 u sections of glutaraldehyde-fixed tissues were similarly incubated, postfixed in osmium tetroxide and embedded in epon for electron microscopy. With both the light and electron microscope acid phosphatase activity was observed in early secretion granules, the most apical Golgi lamella of almost every Golgi apparatus sectioned, "dense bodies" and rarely small Golgi vesicles. This staining was totally inhibited by 5 M sodium fluoride and 2M D-tartaric acid. These observations probably indicate concentration of acid phosphatase by the Golgi apparatus, although they could indicate its functional compartmentalization.