PMID- 2058665
OWN - NLM
STAT- MEDLINE
DCOM- 19910730
LR  - 20171213
IS  - 0002-9513 (Print)
IS  - 0002-9513 (Linking)
VI  - 260
IP  - 6 Pt 1
DP  - 1991 Jun
TI  - Carbohydrate supplementation, glycogen depletion, and amino acid metabolism 
      during exercise.
PG  - E883-90
AB  - Eight highly trained cyclists were studied during exercise after glycogen 
      depletion (test A) and during carbohydrate (CHO) loading (test B). In test B 
      subjects were able to complete 2 h of exercise at 70-75% maximal workload (Wmax), 
      whereas the initial intensity of 70% Wmax had to be reduced to 50% in test A. 
      Plasma ammonia increased more rapidly, and plasma alanine, glutamate, and 
      glutamine were lower in test A. Exercise caused a 3.6-fold increase in the 
      proportion of active branched-chain 2-oxoacid dehydrogenase (BC) complex in 
      muscle in test A. No activation occurred in test B. There was an inverse 
      correlation between the activity of the BC complex and the glycogen content of 
      the postexercise biopsies. Exercise did not cause changes in the muscle content 
      of ATP, ADP, AMP, IMP, hypoxanthine, and lactate. It is concluded that CHO 
      loading abolishes increases in branched-chain amino acid (BCAA) oxidation during 
      exercise and that part of the ammonia production during prolonged exercise 
      originates from deamination of amino acids. The data appear to confirm the 
      hypothesis (A.J. M. Wagenmakers, J.H. Coakley, and R.H.T. Edwards. Int. J. Sports 
      Med. 11: S101-S113, 1990) that acceleration of the BCAA aminotransferase reaction 
      may drain the tricarboxylic acid cycle and that glycogen is a carbon chain 
      precursor of tricarboxylic acid cycle intermediates and glutamine.
FAU - Wagenmakers, A J
AU  - Wagenmakers AJ
AD  - Department of Human Biology, University of Limburg, Maastricht, The Netherlands.
FAU - Beckers, E J
AU  - Beckers EJ
FAU - Brouns, F
AU  - Brouns F
FAU - Kuipers, H
AU  - Kuipers H
FAU - Soeters, P B
AU  - Soeters PB
FAU - van der Vusse, G J
AU  - van der Vusse GJ
FAU - Saris, W H
AU  - Saris WH
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PL  - United States
TA  - Am J Physiol
JT  - The American journal of physiology
JID - 0370511
RN  - 0 (Amino Acids)
RN  - 0 (Blood Glucose)
RN  - 0 (Dietary Carbohydrates)
RN  - 0 (Multienzyme Complexes)
RN  - 0 (Polysaccharides)
RN  - 7664-41-7 (Ammonia)
RN  - 7CVR7L4A2D (maltodextrin)
RN  - 9005-79-2 (Glycogen)
RN  - EC 1.2.- (Ketone Oxidoreductases)
RN  - EC 1.2.4.4 (3-Methyl-2-Oxobutanoate Dehydrogenase (Lipoamide))
SB  - IM
MH  - 3-Methyl-2-Oxobutanoate Dehydrogenase (Lipoamide)
MH  - Adult
MH  - Amino Acids/blood/*metabolism
MH  - Ammonia/blood
MH  - Blood Glucose/metabolism
MH  - *Dietary Carbohydrates
MH  - *Energy Metabolism
MH  - Glycogen/*metabolism
MH  - Humans
MH  - Ketone Oxidoreductases/metabolism
MH  - Male
MH  - Models, Biological
MH  - Multienzyme Complexes/metabolism
MH  - Muscles/metabolism/*physiology
MH  - *Physical Exertion
MH  - *Polysaccharides
MH  - *Sports
OID - NASA: 91281833
EDAT- 1991/06/01 00:00
MHDA- 1991/06/01 00:01
CRDT- 1991/06/01 00:00
PHST- 1991/06/01 00:00 [pubmed]
PHST- 1991/06/01 00:01 [medline]
PHST- 1991/06/01 00:00 [entrez]
AID - 10.1152/ajpendo.1991.260.6.E883 [doi]
PST - ppublish
SO  - Am J Physiol. 1991 Jun;260(6 Pt 1):E883-90. doi: 10.1152/ajpendo.1991.260.6.E883.