PMID- 20505962
OWN - NLM
STAT- MEDLINE
DCOM- 20110420
LR  - 20211020
IS  - 1438-2199 (Electronic)
IS  - 0939-4451 (Print)
IS  - 0939-4451 (Linking)
VI  - 40
IP  - 1
DP  - 2011 Jan
TI  - Differential effects of long-term leucine infusion on tissue protein synthesis in 
      neonatal pigs.
PG  - 157-65
LID - 10.1007/s00726-010-0629-9 [doi]
AB  - Leucine is unique among the amino acids in its ability to promote protein 
      synthesis by activating translation initiation via the mammalian target of 
      rapamycin (mTOR) pathway. Previously, we showed that leucine infusion acutely 
      stimulates protein synthesis in fast-twitch glycolytic muscle of neonatal pigs 
      but this response cannot be maintained unless the leucine-induced fall in amino 
      acids is prevented. To determine whether leucine can stimulate protein synthesis 
      in muscles of different fiber types and in visceral tissues of the neonate in the 
      long-term if baseline amino acid concentrations are maintained, overnight fasted 
      neonatal pigs were infused for 24 h with saline, leucine (400 micromol kg(-1) 
      h(-1)), or leucine with replacement amino acids to prevent the leucine-induced 
      hypoaminoacidemia. Changes in the fractional rate of protein synthesis and 
      activation of mTOR, as determined by eukaryotic initiation factor 4E binding 
      protein (4E-BP1) and S6 kinase 1 (S6K1) phosphorylation, in the gastrocnemius and 
      masseter muscles, heart, liver, jejunum, kidney, and pancreas were measured. 
      Leucine increased mTOR activation in the gastrocnemius and masseter muscles, 
      liver, and pancreas, in both the absence and presence of amino acid replacement. 
      However, protein synthesis in these tissues was increased only when amino acids 
      were infused to maintain baseline levels. There were no changes in mTOR signaling 
      or protein synthesis in the other tissues we examined. Thus, long-term infusion 
      of leucine stimulates mTOR signaling in skeletal muscle and some visceral tissues 
      but the leucine-induced stimulation of protein synthesis in these tissues 
      requires sustained amino acid availability.
FAU - Wilson, Fiona A
AU  - Wilson FA
AD  - Department of Pediatrics, Baylor College of Medicine, United States Department of 
      Agriculture/Agriculture Research Service Children's Nutrition Research Center, 
      Houston, TX, 77030, USA.
FAU - Suryawan, Agus
AU  - Suryawan A
FAU - Orellana, Renan A
AU  - Orellana RA
FAU - Gazzaneo, Maria C
AU  - Gazzaneo MC
FAU - Nguyen, Hanh V
AU  - Nguyen HV
FAU - Davis, Teresa A
AU  - Davis TA
LA  - eng
GR  - K08 AR051563/AR/NIAMS NIH HHS/United States
GR  - R01 AR044474/AR/NIAMS NIH HHS/United States
GR  - R01 AR044474-16/AR/NIAMS NIH HHS/United States
GR  - R01 AR-44474/AR/NIAMS NIH HHS/United States
PT  - Journal Article
PT  - Research Support, N.I.H., Extramural
PT  - Research Support, Non-U.S. Gov't
PT  - Research Support, U.S. Gov't, Non-P.H.S.
DEP - 20100527
PL  - Austria
TA  - Amino Acids
JT  - Amino acids
JID - 9200312
RN  - 0 (Amino Acids)
RN  - 0 (Eukaryotic Initiation Factor-4E)
RN  - GMW67QNF9C (Leucine)
SB  - IM
MH  - Amino Acids/metabolism
MH  - Animals
MH  - Animals, Newborn
MH  - Eukaryotic Initiation Factor-4E/metabolism
MH  - Infusions, Intravenous
MH  - Kidney/drug effects/metabolism
MH  - Leucine/*administration & dosage
MH  - Liver/drug effects/metabolism
MH  - Muscle, Skeletal/drug effects/metabolism
MH  - Pancreas/drug effects/metabolism
MH  - Phosphorylation
MH  - Protein Biosynthesis/*drug effects
MH  - Random Allocation
MH  - Signal Transduction/drug effects
MH  - Swine/genetics/*metabolism
MH  - Time
PMC - PMC3139360
MID - NIHMS306133
EDAT- 2010/05/28 06:00
MHDA- 2011/04/22 06:00
PMCR- 2012/01/01
CRDT- 2010/05/28 06:00
PHST- 2010/03/12 00:00 [received]
PHST- 2010/05/11 00:00 [accepted]
PHST- 2010/05/28 06:00 [entrez]
PHST- 2010/05/28 06:00 [pubmed]
PHST- 2011/04/22 06:00 [medline]
PHST- 2012/01/01 00:00 [pmc-release]
AID - 10.1007/s00726-010-0629-9 [doi]
PST - ppublish
SO  - Amino Acids. 2011 Jan;40(1):157-65. doi: 10.1007/s00726-010-0629-9. Epub 2010 May 
      27.