title: Effect of leucine administration on creatine kinase activity in rat brain.
abstract: Maple syrup urine disease (MSUD) is a metabolic disorder biochemically characterized by the accumulation of branched-chain amino acids (BCAA) and their branched-chain keto acids (BCKA) in blood and tissues. Neurological dysfunction is usually present in the patients, but the pathophysiology of brain damage is still obscure. Considering that brain energy metabolism is possibly altered in MSUD, the main objective of this study was to determine creatine kinase activity in the brain of rats subjected to acute and chronic administration of leucine. Chronic hyperleucinemia was induced by subcutaneous administrations of 4.8 micromol leucine/g body weight, twice a day, from the 6th to the 21st postnatal day. For acute hyperleucinemia, 21-day-old rats received three administrations of the amino acid at 3 h interval. Twelve hours after the chronic treatment or 1 h after the acute one, rats were killed and creatine kinase activity measured. The results indicated that acute or chronic administration of leucine altered creatine kinase activity in the brain of leucine-treated rats. Considering the crucial role creatine kinase plays in energy homeostasis in brain, if these effects also occur in the brain of MSUD patients, it is possible that alteration of this enzyme activity may contribute to the brain damage found in this disease.
authors.affiliation: Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, UFRGS, Porto Alegre, RS, Brazil.
authors.forename: Carmen
authors.initials: C
authors.lastname: Pilla
authors.forename: Rui Felipe
authors.initials: RF
authors.lastname: de Oliveira Cardozo
authors.forename: Carlos Severo
authors.initials: CS
authors.lastname: Dutra-Filho
authors.forename: Angela Terezinha Souza
authors.initials: AT
authors.lastname: Wyse
authors.forename: Moacir
authors.initials: M
authors.lastname: Wajner
authors.forename: Clóvis Milton Duval
authors.initials: CM
authors.lastname: Wannmacher
mesh_terms: D000818:Animals; D001921:Brain / Q000187:drug effects* / Q000201:enzymology*; D003402:Creatine Kinase / Q000378:metabolism*; D004334:Drug Administration Schedule; D007527:Isoenzymes / Q000378:metabolism; D007930:Leucine / Q000008:administration & dosage*; D051381:Rats; D017208:Rats, Wistar; D012016:Reference Values; D014018:Tissue Distribution
chemical_list: D007527:Isoenzymes; D003402:Creatine Kinase; D007930:Leucine