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Renal clearance of branched‐chain L‐amino and 2‐oxo acids in maple syrup urine disease
Author(s) -
Schadewaldt P.,
Hammen> H.W.,
Ott A.C.,
Wendel U.
Publication year - 1999
Publication title -
journal of inherited metabolic disease
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.462
H-Index - 102
eISSN - 1573-2665
pISSN - 0141-8955
DOI - 10.1023/a:1005540016376
Subject(s) - maple syrup urine disease , isoleucine , valine , excretion , medicine , chemistry , endocrinology , renal physiology , leucine , urine , amino acid , renal function , biochemistry
In maple syrup urine disease (MSUD), branched‐chain L‐amino (BCAA) and 2‐oxo acids (BCOA) accumulate in body fluids owing to an inherited deficiency of branched‐chain 2‐oxo acid dehydrogenase complex activity. In MSUD, little information is available on the significance of urinary disposal of branched‐chain compounds. We examined the renal clearance of leucine, valine, isoleucine and alloisoleucine, and their corresponding 2‐oxo acids 4‐methyl‐2‐oxopentanoate (KIC), 3‐methyl‐2‐oxobutanoate (KIV), (S)‐ (S‐KMV), and (R)‐3‐methyl‐2‐oxopentanoate (R‐KMV), using pairs of plasma and urine samples (n=63) from 10 patients with classical MSUD. The fractional renal excretion of free BCAA was in the normal range (<0.5%) and indepen‐dent of the plasma concentrations. The excretion of bound (N‐acylated) BCAA was normal and not significantly dependent on the BCAA plasma concentrations. The fractional renal excretion of BCOA was in the order KIC≪KIV