For 40 years, the amino acid acetyl-DL-leucine (or isoleucine - Tanganil) has been used in clinical practice to reduce imbalance and autonomic manifestations associated with acute vertigo crises. In animal models, acetyl-DL-leucine accelerates vestibular compensation following unilateral labyrinthectomy, and has only minor effects on normal vestibular function. Our work in animal models suggest...

Cancer patients present high mobilization of host protein, with a decrease in lean body mass and body fat depletion occurring in parallel to neoplastic growth. Since leucine is one of the principal amino acids used by skeletal muscle for energy, we investigated the changes in body composition of pregnant tumor-bearing rats after a leucine-supplemented diet. Sixty pregnant Wistar rats divided in...

How protein metabolism is perturbed during chronic glucocorticoid excess is poorly understood. The aims were to investigate the impact of chronic glucocorticoid excess and restoration of eucortisolemia in Cushing's syndrome (CS) on whole body protein metabolism. Eighteen subjects with CS and 18 normal subjects (NS) underwent assessment of body composition using DEXA and whole body protein turno...

Isopropylmalate synthase (IPMS) is the first enzyme in the leucine biosynthetic pathway. It is the branch point in the biosynthesis of leucine and the other branched-chain amino acids. IPMS is also regulated by negative feedback inhibition by the end-product leucine. There are four highly homologous loci within the Arabidopsis thaliana genome, which contain sequences that code for IPMS. Through...

OBJECTIVE To evaluate the effect of leucine and genistein on the dopaminergic system in a rat model of schizophrenia. METHODS Behavioral effects of leucine and genistein on apomorphine induced stereotyped behavior, haloperidol induced catalepsy, foot shock induced aggression, and apomorphine induced locomotor activity were conducted. In each of these tests, the leucine (0.7g/kg p.o.) and geni...

Aging is characterized by a progressive loss of muscle mass. A decrease of muscle protein synthesis stimulation has been detected in the postprandial state and correlated to a decrease of muscle protein synthesis sensitivity to leucine in vitro. This study was undertaken to examine the effect of a leucine-supplemented meal on postprandial (PP) muscle protein synthesis during aging. Adult (8 mo ...

Culturing rat islets in high glucose (HG) increased 1-Cketoisocaproate (KIC) oxidation compared with culturing them in low glucose. Leucine caused insulin secretion (IS) in low glucose but not in HG rat islets, whereas KIC did so in both. Pretreatment with HG for 40 min abolished leucine stimulation of IS by mouse islets and prevented the cytosolic Ca rise without inhibiting IS and Ca increment...

In this study, we addressed the direct effect of leucine on insulin signaling. In investigating the associated mechanisms, we found that leucine itself does not activate the classical Akt- or ERK1/2 MAP kinase-dependent signaling pathways but can facilitate the insulin-induced phosphorylations of Akt(473) and ERK1/2 in a time- and dose-dependent manner in cultured hepatocytes. The leucine-facil...

The biosynthesis of kitasamycin in Streptomyces kitasatoensis B-896 was profoundly influenced by the addition of precursors to complex and defined media: l-valine and l-leucine directed biosynthesis towards the pairs A(4)/A(5) (R(2) = butyryl) and A(1)/A(3) (R(2) = isovaleryl), respectively, and total kitasamycin titers were doubled and quadrupled, respectively. S. kitasatoensis B-896 was very ...

Leucine and glutamine were used to elicit biphasic insulin release in rat pancreatic islets. Leucine did not mimic the full biphasic response of glucose. Glutamine was without effect. However, the combination of the two did mimic the biphasic response. When the ATP-sensitive K+ (KATP) channel-independent pathway was studied in the presence of diazoxide and KCl, leucine and its nonmetabolizable ...