Authors: Schadewaldt P; Dalle-Feste C; Langenbeck U; Wendel U
Abstract: Total body and renal elimination of L-alloisoleucine was assessed after oral loads (0.57 mmol/kg body wt) in four healthy subjects and in five patients with maple syrup urine disease (MSUD) of different degrees of severity. As judged from the fictive initial concentration, L-alloisoleucine is distributed evenly in the total body water space. In the controls, estimated half-time of total elimination was 9.2 +/- 2.2 h (n = 4). In the MSUD patients, it ranged from 26 h (mild variant) to about 8 d (classical type). Because of its low renal clearance rate, L-alloisoleucine was cleared through ketomethylvalerate to greater than 99% in normals and to at least 73% in the MSUD patients. Assuming small variation in the losses of ketomethylvalerate through L-isoleucine formation and through renal excretion, this test allows ranking of MSUD patients with regard to their residual in vivo branched-chain oxo-acid dehydrogenase activity.
Keywords: 3-Methyl-2-Oxobutanoate Dehydrogenase (Lipoamide); Administration, Oral; Adolescent; Child; Female; Half-Life; Humans; Isoleucine/administration & dosage/blood/*pharmacokinetics; Keto Acids/metabolism; Ketone Oxidoreductases/metabolism; Kidney/metabolism; Maple Syrup Urine Disease/*metabolism; Multienzyme Complexes/metabolism; Tissue Distribution|
Journal: Pediatric research Volume: 30 Issue: 5 Pages: 430-4 Date: Nov. 1, 1991 PMID: 1754297 |
Schadewaldt P, Dalle-Feste C, Langenbeck U, Wendel U (1991) Oral L-alloisoleucine loading studies in healthy subjects and in patients with maple syrup urine disease. Pediatric research 30: 430-4.
Comment on This Data Unit