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...

Allison, Milton J. (Dairy Cattle Research Branch, U. S. Department of Agriculture, Beltsville, Md.), M. P. Bryant, and R. N. Doetsch. Studies on the metabolic function of branched-chain volatile fatty acids, growth factors for ruminococci. I. Incorporation of isovalerate into leucine. J. Bacteriol. 83:523-532. 1962.-Ruminococcus flavefaciens strain C94, a cellulolytic rumen bacterium, requires ...

An acute unilateral vestibular lesion leads to a vestibular tone imbalance with nystagmus, head roll tilt and postural imbalance. These deficits gradually decrease over days to weeks due to central vestibular compensation (VC). This study investigated the effects of i.v. N-acetyl-DL-leucine, N-acetyl-L-leucine and N-acetyl-D-leucine on VC using behavioural testing and serial [18F]-Fluoro-desoxy...

Enhanced protein synthesis in skeletal muscle after ingestion of a balanced meal in postabsorptive rats is mimicked by oral leucine administration. To assess the contribution of insulin to the protein synthetic response to leucine, food-deprived (18 h) male rats (approximately 200 g) were intravenously administered a primed-constant infusion of somatostatin (60 microg + 3 microg.kg(-1).h(-1)) o...

Bergmann and Stein (1) have described a procedure for the isolation and purification of naturally occurring n-leucine based upon the precipitation and recrystallization of the slightly soluble salt of this amino acid with naphthalene-fi-sulfonic acid. The product obtained was stated to be 97 per cent pure and to be free from methionine, a common contaminant of less pure preparations of n-leucin...

BACKGROUND Leucine may function as a signaling molecule to regulate metabolism. We have previously shown that dietary leucine supplementation significantly improves glucose and energy metabolism in diet-induced obese mice, suggesting that leucine supplementation could potentially be a useful adjuvant therapy for obesity and type 2 diabetes. Since the underlying cause for obesity and type 2 diab...

Three experiments were carried out on a total of 78 female rats to examine the effect of an excess intake of leucine, with and without additions of vitamin B6 and/or niacin, on the excretion of tryptophan and niacin metabolites, and on branched-chain amino acid transaminase activity in some organs and on serum amino acid levels. An excess in take of leucine (10% leucine) retarded the growth of ...

Leptin biosynthesis in adipose cells in vivo is increased by food intake and decreased by food deprivation. However, the mechanism that couples leptin production to food intake remains unknown. We found that addition of leucine to isolated rat adipocytes significantly increased leptin production by these cells, suggesting that postprandial leptin levels may be directly regulated by dietary leuc...

In this study, food-deprived (18 h) control rats and rats with alloxan-induced diabetes were orally administered saline or the amino acid leucine to assess whether it regulates protein synthesis independently of a change in serum insulin concentrations. Immediately after leucine administration, diabetic rats were infused with insulin (0.0, 4.0, or 20 pmol small middle dot min(-1) small middle d...

Leucine and leptin play important roles in regulating protein synthesis and degradation in skeletal muscles in vitro and in vivo. However, the objective of the present study was to determine whether leptin and leucine function synergistically in regulating protein metabolism of skeletal muscles. In the in vitro experiment, C2C12 myotubes were cultured for 2 h in the presence of 5 mm-leucine and...