One hundred and one young-adult female Sprague-Dawley rats were acclimatized to metabolic cages for 2 days. After that time 24-hour urine was collected at a constant cooling temperature of 0-4 degrees C. After gel filtration the enzyme activities were determined, and the resulting values were used to calculate 24-hour excretions. The following reference ranges (2.5 and 97.5 percentiles) were de...

Dietary leucine has been suspected to play an important role in insulin release, a hormone that controls satiety and metabolism. The mechanism by which insulin-producing cells (IPCs) sense leucine and regulate insulin secretion is still poorly understood. In Drosophila, insulin-like peptides (DILP2 and DILP5) are produced by brain IPCs and are released in the hemolymph after leucine ingestion. ...

Leucine is the only physiologic amino acid that can stimulate insulin release by itself, and a great deal of evidence suggests that leucine does this by allosterically activating glutamate dehydrogenase (GDH). GDH catalyzes the oxidative deamination of endogenous glutamate, which is present at a high concentration in the pancreatic b-cell. Studies that support this role of leucine include the f...

The distribution of bacterial leucine dehydrogenase (L-leucine:NAD+ oxidoreductase, deaminating, EC 1.4.1.9) was investigated, and Bacillus sphaericus (IFO 3525) was found to have the highest activity of the enzyme. Leucine dehydrogenase, which was purified to homogeneity and crystallized from B. sphaericus, has a molecular weight of about 245,000 and consists of six identical subunits (Mr = 41...

Six leucine auxotrophic strains of the white rot basidiomycete Phanerochaete chrysosporium were characterized genetically and biochemically. Complementation studies involving the use of heterokaryons identified three leucine complementation groups. Since all of the leucine auxotrophs grew on minimal medium supplemented with alpha-ketoisocaproate as well as with leucine, the transaminase catalyz...

Acute administration of leucine and norleucine activates the mammalian target of rapamycin (mTOR) cell-signaling pathway and increases rates of protein synthesis in a number of tissues in fasted rats. Although persistent stimulation of mTOR signaling is thought to increase protein synthetic capacity, little information is available concerning the effects of chronic administration of these agoni...

BACKGROUND/OBJECTIVES The study was conducted to evaluate the effects of dietary leucine supplementation on mitochondrial biogenesis and energy metabolism in the liver of normal birth weight (NBW) and intrauterine growth-retarded (IUGR) weanling piglets. MATERIALS/METHODS A total of sixteen pairs of NBW and IUGR piglets from sixteen sows were selected according to their birth weight. At postn...

Amino acid dehydrogenases (AADHs) are a group of enzymes that catalyze the reversible reductive amination keto acids with ammonia to produce chiral amino using either nicotinamide adenine dinucleotide (NAD+) or phosphate (NADP+) as cofactors. Among them, glutamate dehydrogenase, valine leucine phenylalanine and tryptophan dehydrogenase have been classified superfamily (s-AADHs) by previous rese...