Calcium ion transport across plasma membranes isolated from rat kidney cortex

Biochem J. 1979 Mar 15;178(3):549-57. doi: 10.1042/bj1780549.

Abstract

Basal-lateral-plasma-membrane vesicles and brush-border-membrane vesicles were isolated from rat kidney cortex by differential centrifugation followed by free-flow-electrophoresis. Ca2+ uptake into these vesicles was investigated by a rapid filtration method. Both membranes show a considerable binding of Ca2+ to the vesicle interior, making the analysis of passive fluxes in uptake experiments difficult. Only the basal-lateral-plasma-membrane vesicles exhibit an ATP-dependent pump activity which can be distinguished from the activity in mitochondrial and endoplasmic reticulum by virtue of the different distribution during free-flow electrophoresis and its lack of sensitivity to oligomycin. The basal-lateral plasma membranes contain in addition a Na+/Ca2+-exchange system which mediates a probably rheogenic counter-transport of Ca2+ and Na+ across the basal cell border. The latter system is probably involved in the secondary active Na+-dependent and ouabain-inhibitable Ca2+ reabsorption in the proximal tubule, the ATP-driven system is probably more important for the maintenance of a low concentration of intracellular Ca2+.

MeSH terms

  • Adenosine Triphosphate / pharmacology
  • Animals
  • Biological Transport / drug effects
  • Biological Transport, Active / drug effects
  • Calcium / metabolism*
  • Cell Membrane / metabolism
  • In Vitro Techniques
  • Kidney Cortex / cytology*
  • Kidney Cortex / drug effects
  • Kidney Cortex / metabolism
  • Male
  • Models, Biological
  • Rats
  • Sodium / metabolism
  • Sodium / pharmacology

Substances

  • Adenosine Triphosphate
  • Sodium
  • Calcium