Ultracytochemical Study of the Pathway of Ca^<2+> Transportation across the Epithelial Cell Layer of a Nephron

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Author(s)

    • FUJIOKA Atsuko
    • Department of Anatomy, Kinki University School of Medicine Osaka-Sayama
    • SASAKI Hiroshi
    • Department of Anatomy, Kinki University School of Medicine Osaka-Sayama

Abstract

The pathway of Ca<SUP>2+</SUP> absorption across the renal epithelial layer was ultracytochemically investigated in nephrons using an oxalate-pyroantimonate technique. Reaction products were strongly detected in the inter-cellular space in proximal tubules, and in intracellular organelles in distal tubules in the cortex and the outer layer of the outer medulla. These findings are suggestive of paracellular transport of Ca<SUP>2+</SUP> in the proximal tubule, and transcellular transport in the distal tubule. The transcellular pathway of Ca<SUP>2+</SUP> is of interest, as intracellular Ca<SUP>2+</SUP> concentrations must be maintained. Ca-precipitates, in the distal tubule cells, were detected en masse in mitochondria, and to a lesser extent, in smooth endoplasmic reticulum, Golgi apparatus and vesicles. Precipitates were rare in lysosomes and rough endoplasmic reticulum. Calcium containing organelles distributed throughout the cytoplasm. Free precipitates in the cytoplasmic matrix were only rarely seen in the apical portion of the cells. It seems that Ca<SUP>2+</SUP>immediately after entering a cell, binds to calcium binding proteins, or is sequestered to organelles like mitochondria, Golgi apparatus, smooth endoplasmic reticulum or vesicles. In this way, fluctuations in intra-cellular Ca<SUP>2+</SUP> concentrations are avoided. These organelles may be involved in Ca-transport in Ca-absorbing cells.

Journal

  • ACTA HISTOCHEMICA ET CYTOCHEMICA

    ACTA HISTOCHEMICA ET CYTOCHEMICA 30(2), 193-201, 1997-04-01

    JAPAN SOCIETY OF HISTOCHEMISTRY AND CYTOCHEMISTRY

References:  36

Codes

  • NII Article ID (NAID)
    10008606586
  • NII NACSIS-CAT ID (NCID)
    AA00508022
  • Text Lang
    ENG
  • Article Type
    ART
  • ISSN
    00445991
  • Data Source
    CJP  J-STAGE 
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