PMID- 10720160
OWN - NLM
STAT- MEDLINE
DCOM- 20000330
LR  - 20220227
IS  - 0022-3166 (Print)
IS  - 0022-3166 (Linking)
VI  - 130
IP  - 2
DP  - 2000 Feb
TI  - Orally administered leucine stimulates protein synthesis in skeletal muscle of 
      postabsorptive rats in association with increased eIF4F formation.
PG  - 139-45
AB  - We investigated the protein synthetic response of skeletal muscle to an orally 
      administered dose of leucine given alone or in combination with carbohydrate. 
      Male rats were freely fed (F) or food deprived for 18 h; food-deprived rats were 
      then administered saline (S), carbohydrate (CHO), leucine (L) or a combination of 
      carbohydrate plus leucine (CL). CHO and CL meals were isocaloric and provided 15% 
      of daily energy requirements. L and CL meals each delivered 270 mg leucine. 
      Muscle protein synthesis in S was 65% of F (P<0.01) 1 h after meal 
      administration. Concomitant with lower rates of protein synthesis, 
      phosphorylation of the translational repressor, eukaryotic initiation factor 
      (eIF)4E-binding protein 1 (4E-BP1), was less in S, leading to greater association 
      of 4E-BP1.eIF4E, and reduced formation of the active eIF4G.eIF4E complex compared 
      with F (P<0.01). Oral administration of leucine (L or CL), but not CHO, restored 
      protein synthesis equal to that in F and resulted in 4E-BP1 phosphorylation that 
      was threefold greater than that of S (P<0.01). Consequently, formation of 
      4E-BP1.eIF4E was inhibited and eIF4G.eIF4E was not different from F. The amount 
      of eIF4E in the phosphorylated form was greater in S and CHO (P<0.01) than in all 
      other groups. In contrast, no differences in the phosphorylation state of 
      eIF2alpha or the activity of eIF2B were noted among treatment groups. Serum 
      insulin was elevated 2.6- and 3.7-fold in CHO and CL, respectively, but was not 
      different in L, compared with S (P<0.05). These results suggest that leucine 
      stimulates protein synthesis in skeletal muscle by enhancing eIF4F formation 
      independently of increases in serum insulin.
FAU - Anthony, J C
AU  - Anthony JC
AD  - Department of Cellular and Molecular Physiology, The Pennsylvania State 
      University College of Medicine, Hershey 17033, USA.
FAU - Anthony, T G
AU  - Anthony TG
FAU - Kimball, S R
AU  - Kimball SR
FAU - Vary, T C
AU  - Vary TC
FAU - Jefferson, L S
AU  - Jefferson LS
LA  - eng
GR  - DK-15658/DK/NIDDK NIH HHS/United States
GR  - GM-08619/GM/NIGMS NIH HHS/United States
GR  - GM-39277/GM/NIGMS NIH HHS/United States
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PT  - Research Support, U.S. Gov't, P.H.S.
PL  - United States
TA  - J Nutr
JT  - The Journal of nutrition
JID - 0404243
RN  - 0 (Dietary Carbohydrates)
RN  - 0 (Eukaryotic Initiation Factor-4F)
RN  - 0 (Muscle Proteins)
RN  - 0 (Peptide Initiation Factors)
RN  - GMW67QNF9C (Leucine)
SB  - IM
MH  - Administration, Oral
MH  - Animals
MH  - Dietary Carbohydrates/administration & dosage/*pharmacology
MH  - Eukaryotic Initiation Factor-4F
MH  - Food Deprivation
MH  - Leucine/administration & dosage/blood/*pharmacology
MH  - Male
MH  - Muscle Proteins/*biosynthesis
MH  - Muscle, Skeletal/*drug effects/*metabolism
MH  - Peptide Initiation Factors/*biosynthesis/drug effects/metabolism
MH  - Phosphorylation/drug effects
MH  - Rats
MH  - Rats, Sprague-Dawley
EDAT- 2000/03/17 09:00
MHDA- 2000/04/01 09:00
CRDT- 2000/03/17 09:00
PHST- 2000/03/17 09:00 [pubmed]
PHST- 2000/04/01 09:00 [medline]
PHST- 2000/03/17 09:00 [entrez]
AID - 10.1093/jn/130.2.139 [doi]
PST - ppublish
SO  - J Nutr. 2000 Feb;130(2):139-45. doi: 10.1093/jn/130.2.139.