PMID- 17409123
OWN - NLM
STAT- MEDLINE
DCOM- 20070830
LR  - 20200930
IS  - 0363-6143 (Print)
IS  - 0363-6143 (Linking)
VI  - 293
IP  - 1
DP  - 2007 Jul
TI  - The deleterious effects of bed rest on human skeletal muscle fibers are 
      exacerbated by hypercortisolemia and ameliorated by dietary supplementation.
PG  - C313-20
AB  - Prolonged inactivity associated with bed rest in a clinical setting or 
      spaceflight is frequently associated with hypercortisolemia and inadequate 
      caloric intake. Here, we determined the effect of 28 days of bed rest (BR); bed 
      rest plus hypercortisolemia (BRHC); and bed rest plus essential amino acid (AA) 
      and carbohydrate (CHO) supplement (BRAA) on the size and function of single slow- 
      and fast-twitch muscle fibers. Supplementing meals, the BRAA group consumed 16.5 
      g essential amino acids and 30 g sucrose at 1100, 1600, and 2100 h, and the BRHC 
      subjects received 5 daily doses of 10-15 mg of oral hydrocortisone sodium 
      succinate throughout bed rest. Bed rest induced atrophy and loss of force (mN) 
      and power (muN.FL.s(-1)) in single fibers was exacerbated by hypercortisolemia 
      where soleus peak force declined by 23% in the type I fiber from a prevalue of 
      0.78 +/- 0.02 to 0.60 +/- 0.02 mN post bed rest (compared to a 7% decline with 
      bed rest alone) and 27% in the type II fiber (1.10 +/- 0.08 vs. 0.81 +/- 0.05 
      mN). In the BRHC group, peak power dropped by 19, 15, and 11% in the soleus type 
      I, and vastus lateralis (VL) type I and II fibers, respectively. The AA/CHO 
      supplement protected against the bed rest-induced loss of peak force in the type 
      I soleus and peak power in the VL type II fibers. These results provide evidence 
      that an AA/CHO supplement might serve as a successful countermeasure to help 
      preserve muscle function during periods of relative inactivity.
FAU - Fitts, R H
AU  - Fitts RH
AD  - Dept. of Biology, Marquette University, Wehr Life Sciences Bldg., PO Box 1881, 
      Milwaukee, WI 53201-1881, USA. robert.fitts@mu.edu
FAU - Romatowski, J G
AU  - Romatowski JG
FAU - Peters, J R
AU  - Peters JR
FAU - Paddon-Jones, D
AU  - Paddon-Jones D
FAU - Wolfe, R R
AU  - Wolfe RR
FAU - Ferrando, A A
AU  - Ferrando AA
LA  - eng
GR  - P30 AG024832/AG/NIA NIH HHS/United States
PT  - Journal Article
PT  - Randomized Controlled Trial
PT  - Research Support, Non-U.S. Gov't
PT  - Research Support, U.S. Gov't, Non-P.H.S.
DEP - 20070404
PL  - United States
TA  - Am J Physiol Cell Physiol
JT  - American journal of physiology. Cell physiology
JID - 100901225
RN  - 0 (Amino Acids, Essential)
RN  - 0 (Dietary Sucrose)
RN  - LIU00Z1Z84 (hydrocortisone hemisuccinate)
RN  - WI4X0X7BPJ (Hydrocortisone)
SB  - IM
MH  - Adult
MH  - Amino Acids, Essential/*administration & dosage
MH  - Bed Rest/*adverse effects
MH  - Chronic Disease
MH  - Cushing Syndrome/chemically induced/*complications/pathology/physiopathology
MH  - Dietary Sucrose/*administration & dosage
MH  - Humans
MH  - Hydrocortisone/analogs & derivatives
MH  - Male
MH  - Muscle Contraction/drug effects
MH  - Muscle Fibers, Fast-Twitch/drug effects/pathology
MH  - Muscle Fibers, Slow-Twitch/drug effects/pathology
MH  - Muscle Strength/drug effects
MH  - Muscle, Skeletal/*drug effects/pathology/physiopathology
MH  - Muscular Atrophy/*etiology/pathology/physiopathology/*prevention & control
MH  - Time Factors
MH  - Treatment Outcome
EDAT- 2007/04/06 09:00
MHDA- 2007/08/31 09:00
CRDT- 2007/04/06 09:00
PHST- 2007/04/06 09:00 [pubmed]
PHST- 2007/08/31 09:00 [medline]
PHST- 2007/04/06 09:00 [entrez]
AID - 00573.2006 [pii]
AID - 10.1152/ajpcell.00573.2006 [doi]
PST - ppublish
SO  - Am J Physiol Cell Physiol. 2007 Jul;293(1):C313-20. doi: 
      10.1152/ajpcell.00573.2006. Epub 2007 Apr 4.