title: Calcium containing lysosomes in the normal chick duodenum: a histochemical and analytical electron microscopic study.
abstract: Absorptive cells of the normal chick duodenum contain numerous supranuclear vesicular/vacuolar structures. By routine transmission electron microscopy, such structures are membrane bound and demonstrate a granular content. These vesicles appear to move laterally and eventually coalesce with the lateral plasma membrane (exocytosis). The granular contents are resistant to high temperature microincineration, thus revealing their mineral-containing nature. The granular vesicular matrix also stains intensely with osmium pyroantimonate EGTA chelation of pyroantimonate-stained vesicles selectively extracts the granules indicating a high concentration of calcium. X-ray microanalysis also demonstrates a significant intravesicular calcium localization. When tissues were incubated for the presence of acid phosphatase, the supranuclear vesicles were markedly positive for this lysosomal enzyme. A possible role for these calcium-containing lysosomes in the transcellular flux of calcium ions across the intestinal absorptive cell is discussed.
mesh_terms: D000135:Acid Phosphatase / Q000378:metabolism; D000818:Animals; D002118:Calcium / Q000032:analysis*; D002645:Chickens; D004386:Duodenum / Q000648:ultrastructure*; D004577:Electron Probe Microanalysis; D006651:Histocytochemistry; D006358:Hot Temperature; D008247:Lysosomes / Q000032:analysis* / Q000201:enzymology; D008297:Male
chemical_list: D000135:Acid Phosphatase; D002118:Calcium