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Decreased uptake of L‐cystine by duodenal brush border membrane vesicles from patients with cystinuria
Author(s) -
Furlong T. J.,
Stiel D.
Publication year - 1993
Publication title -
australian and new zealand journal of medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.596
H-Index - 70
eISSN - 1445-5994
pISSN - 0004-8291
DOI - 10.1111/j.1445-5994.1993.tb01728.x
Subject(s) - cystinuria , brush border , cystine , vesicle , membrane , microvillus , medicine , aminoaciduria , biochemistry , chemistry , cysteine , amino acid , enzyme
Background:The pathophysiology of cystinuria remains unclear. Decreased absorption of L‐cystine across brush border membranes of small intestinal and renal proximal tubular epithelial cells is likely but has not been directly demonstrated.Aims:To compare the rates of L‐cystine transport by isolated duodenal brush border membranes of normal individuals and patients with cystinuria.Methods:Distal duodenal biopsies were taken from normal individuals and patients with cystinuria. Brush border membrane vesicles (BBMV) were prepared using magnesium aggregation and differential centrifugation and the rates of L‐cystine transport into the vesicles measured using a rapid filtration technique.Results:Rates of L‐cystine transport by BBMV from patients with cystinuria were reduced at 5 minute (p = 0.003) and 30 minute (/> = 0.053). Time points, indicating that L‐cystine absorption across brush border membranes is abnormal in cystinuria. (Aust NZ J Med 1993; 23: 258–263.)