PMID- 8519162
OWN - NLM
STAT- MEDLINE
DCOM- 19930726
LR  - 20190920
IS  - 0144-5979 (Print)
IS  - 0144-5979 (Linking)
VI  - 13
IP  - 3
DP  - 1993 May
TI  - No effect of carbohydrate feeding on glycogen synthase in human muscle during 
      exercise.
PG  - 265-70
AB  - The effect of carbohydrate (CHO) feedings on exercise-mediated changes in 
      glycogen synthase fractional (GSF) activity has been investigated. Subjects 
      cycled at approximately 70% of maximal oxygen uptake on two occasions: the first 
      to fatigue (135 +/- 17 min; mean +/- SE) (control, CON), and the second at the 
      same workload and duration as the first, but with the addition of frequent 
      ingestion of CHO during exercise (0.27 g kg-1 body weight every 15 min). Biopsies 
      were taken from the quadriceps femoris muscle before and immediately after 
      exercise. Plasma glucose and insulin decreased during CON exercise, but remained 
      elevated throughout CHO exercise (end of exercise: glucose = 4.4 +/- 0.2 mM CON 
      vs. 5.8 +/- 0.2 CHO, P < 0.01; insulin = 9 +/- 1 uU ml-1 CON vs. 19 +/- 3 CHO, P 
      < 0.05). Glycogen decreased to approximately 10% of the basal value during CON 
      and to approximately 20% during CHO, and there was no significant difference in 
      net glycogenolysis between treatments. GSF activity averaged 0.25 +/- 0.03 and 
      0.22 +/- 0.05 at rest, and increased to 0.51 +/- 0.08 and 0.48 +/- 0.09 after 
      exercise in CON and CHO, respectively (P > 0.05 between treatments). It is 
      concluded that under the present conditions CHO feedings do not alter the 
      exercise-mediated changes in GSF activity. The increase in GSF during exercise is 
      attributed at least in part to the decrease in muscle glycogen (which increases 
      the suitability of GS as substrate for GS phosphatase).
FAU - Yan, Z
AU  - Yan Z
AD  - Department of Kinesiology, University of Illinois, Urbana.
FAU - Spencer, M K
AU  - Spencer MK
FAU - Katz, A
AU  - Katz A
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PL  - England
TA  - Clin Physiol
JT  - Clinical physiology (Oxford, England)
JID - 8309768
RN  - 0 (Dietary Carbohydrates)
RN  - 0 (Fatty Acids, Nonesterified)
RN  - 9005-79-2 (Glycogen)
RN  - EC 2.4.1.11 (Glycogen Synthase)
RN  - V50K1D7P4Y (Uridine Diphosphate Glucose)
SB  - IM
MH  - Adolescent
MH  - Adult
MH  - Dietary Carbohydrates/*pharmacology
MH  - Exercise/*physiology
MH  - Fatty Acids, Nonesterified/blood
MH  - Female
MH  - Gluconeogenesis/drug effects
MH  - Glycogen/metabolism
MH  - Glycogen Synthase/*metabolism
MH  - Heart Rate/physiology
MH  - Humans
MH  - Male
MH  - Middle Aged
MH  - Muscles/drug effects/*enzymology
MH  - Physical Endurance/physiology
MH  - Respiration/physiology
MH  - Uridine Diphosphate Glucose/metabolism
EDAT- 1993/05/01 00:00
MHDA- 1993/05/01 00:01
CRDT- 1993/05/01 00:00
PHST- 1993/05/01 00:00 [pubmed]
PHST- 1993/05/01 00:01 [medline]
PHST- 1993/05/01 00:00 [entrez]
AID - 10.1111/j.1475-097x.1993.tb00326.x [doi]
PST - ppublish
SO  - Clin Physiol. 1993 May;13(3):265-70. doi: 10.1111/j.1475-097x.1993.tb00326.x.