BACKGROUND The 1985 FAO/WHO/UNU requirement for leucine is too low according to tracer-derived estimates of leucine oxidation and balance in adults from developed regions. OBJECTIVE The leucine requirement in populations in developing countries was assessed with use of the 24-h tracer balance method and on the basis of nitrogen balances. DESIGN Twenty healthy Indian men were studied during ...

Changes in the kinetics of leucine in the mammary gland were examined in four lactating goats (25, 38, 45, and 135 DIM) that were given an i.v. infusion of a mixture of 18 AA, not including leucine, to alter the availability of leucine to the gland relative to other AA. Arteriovenous monitoring of [1-13C]leucine kinetics across one-half of the mammary gland was conducted on the last day (d 6 or...

Two trials were conducted to estimate the leucine requirement of sows during a 21-day lactation. In trial 1, hominy feed, geletin, corn sugar, vitamins, minerals and indispensable amino acids were used to formulate a diet containing adequate levels of all essential nutrients except leucine. L-leucine was added to this mixture to produce five diets containing: .44 (basal), .64, .84, 1.04 and 1.2...

Circulating levels of 8-leucine are elevated in the cobalamin-deficient state of pernicious anemia. Levels of leucine, on the other hand, are much lower. It is proposed that leucine 2,3-aminomutase, the cobalamindependent enzyme that catalyzes the interconversion of leucine and 8-leucine, is the affected enzyme in pernicious anemia and causes these results by preventing the synthesis of leucine...

L-Leucine is known to stimulate protein synthesis in L6 myotubes. In the present study, we examined the possible involvement of calcium signaling pathways in the stimulation of protein synthesis induced by L-leucine in L6 myotubes. After 16 h of treatment with L-leucine-depleted medium, the re-addition of L-leucine for 4 h augmented protein synthesis by about 50% as compared with an L-leucine-d...

Lack of insulin results in a catabolic state in subjects with insulin-dependent diabetes mellitus which is reversed by insulin treatment. Amino acid supply, especially branched chain amino acids such as leucine, enhances protein synthesis in both animal and human studies. This small study was undertaken to assess the acute effect of supplemental leucine on protein metabolism in adolescents with...

To analyze genetic effects on milk production traits, 164 unrelated Italian Jersey cows reared in 15 farms located in Southern Italy were characterized at the growth hormone locus. Using a Polymerase Chain Reaction-Restriction Fragment Length Polymorphism protocol all three possible genotypes for the Leucine/Valine polymorphism were identified even if in the considered population the number of ...

Fetuses of eight pregnant ewes (114-117 d of gestation) were used to study whether fetal insulin concentration affects fetal protein accretion and, if so, whether such changes are caused by effects on protein synthesis or protein breakdown. Fetal leucine kinetics were measured by infusion of [1-14C]leucine during each of three protocols: (I) low vs. normal insulin concentration; (II) low vs. hi...

Amino acids and insulin have anabolic effects in skeletal muscle, but the mechanisms are poorly understood. To test the hypothesis that leucine and insulin stimulate translation initiation in human skeletal muscle by phosphorylating 70-kDa ribosomal protein S6 kinase (p70(S6k)), we infused healthy adults with leucine alone (n = 6), insulin alone (n = 6), or both leucine and insulin (n = 6) for ...