Renal cortical brush-border and basolateral membranes: Cholesterol and phospholipid Composition and relative turnover

Bruce Molitoris, Francis R. Simon

Research output: Contribution to journalArticle

101 Citations (Scopus)

Abstract

A new procedure for the rapid isolation of renal cortical brush-border and basolateral membranes from the same homogenate is described. Brush-border membranes isolated using Mg2+-EGTA precipitation were enriched 18-fold for leucine aminopeptidase and had a recovery of 32.5%. Basolateral membrane fractions were isolated using a discontinuous sucrose gradient and showed an enrichment of 10.7-fold and recovery of 12.8% using (Na+, K+)-ATPase as a marker enzyme. Lipid analysis using two-dimensional TLC separation of phospholipids and gas liquid chromatography for cholesterol showed marked differences in the lipid composition of the brush-border and basolateral membranes. The brush-border membrane had increased sphingomyelin, phosphatidylserine, ethanolamine plasmalogens, and an increased cholesterol-to-phospholipid and sphingomyelin-to-phosphatidylcholine ratio compared to the basolateral membrane. The relative turnover of total membrane and individual phospholipid species using a double isotope ratio method was carried out. Phospholipids were labeled with either phosphorus 32 and 33 or acetate (3H, 1-14C). The relative turnover of phospholipid species and cholesterol differed strikingly. Phosphatidylcholine showed a high turnover, phosphatidylethanolamine and phosphatidylinositol had intermediate values and sphingomyelin, phosphatidylserine and cholesterol had low relative turnover rates. The order of phospholipid class relative turnover was independent of the labeled precursor used. The brush-border membrane had a significantly reduced relative turnover rate for total membrane phospholipids, sphingomyelin and cholesterol compared to the basolateral membrane. These data show marked differences in the lipid composition and relative turnover rates of the phospholipid species of the brush-border and basolateral membranes. They provide a biochemical basis for the recently reported differences in brush-border and basolateral membrane fluidity and suggest independent cellular regulation of brush-border and basolateral membrane lipids.

Original languageEnglish (US)
Pages (from-to)207-215
Number of pages9
JournalJournal of Membrane Biology
Volume83
Issue number3
DOIs
StatePublished - Oct 1985
Externally publishedYes

Fingerprint

Microvilli
Phospholipids
Cholesterol
Kidney
Membranes
Sphingomyelins
Phosphatidylserines
Phosphatidylcholines
Lipids
Leucyl Aminopeptidase
Membrane Fluidity
Egtazic Acid
Membrane Lipids
Phosphatidylinositols
Isotopes
Gas Chromatography
Phosphorus
Sucrose
Acetates

Keywords

  • basolateral membranes
  • brush-border membranes
  • cholesterol
  • phospholipids
  • turnover

ASJC Scopus subject areas

  • Physiology
  • Cell Biology
  • Biophysics

Cite this

Renal cortical brush-border and basolateral membranes : Cholesterol and phospholipid Composition and relative turnover. / Molitoris, Bruce; Simon, Francis R.

In: Journal of Membrane Biology, Vol. 83, No. 3, 10.1985, p. 207-215.

Research output: Contribution to journalArticle

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