PMID- 8076616
OWN - NLM
STAT- MEDLINE
DCOM- 19941006
LR  - 20190830
IS  - 0301-5548 (Print)
IS  - 0301-5548 (Linking)
VI  - 68
IP  - 5
DP  - 1994
TI  - Effects of glucose ingestion or glucose infusion on fuel substrate kinetics 
      during prolonged exercise.
PG  - 381-9
AB  - To determine if bypassing both intestinal absorption and hepatic glucose uptake 
      by intravenous glucose infusion might increase the rate of muscle glucose 
      oxidation above 1 g.min-1, ten endurance-trained subjects were studied during 125 
      min of cycling at 70% of peak oxygen uptake (VO2peak). During exercise the 
      subjects ingested either a 15 g.100 ml-1 U-14C labelled glucose solution or H2O 
      labelled with a U-14C glucose tracer for the determination of the rates of plasma 
      glucose oxidation (Rox) and exogenous carbohydrate (CHO) oxidation from plasma 
      14C glucose and 14CO2 specific activities, and respiratory gas exchange. 
      Simultaneously, 2-3H glucose was infused at a constant rate to measure glucose 
      turnover, while unlabelled glucose (25% dextrose) was infused into those subjects 
      not ingesting glucose to maintain plasma glucose concentration at 5 mmol.l-1. 
      Despite similar plasma glucose concentrations [ingestion 5.3 (SEM 0.13) mmol.l-1; 
      infusion 5.0 (0.09) mmol.l-1], compared to glucose infusion, CHO ingestion 
      significantly increased plasma insulin concentrations [12.9 (1.0) vs 4.8 (0.5) 
      mU.l-1; P < 0.05], raised total Rox values [9.5 (1.2) vs 6.2 (0.7) mmol.125 min-1 
      kg fat free mass-1 (FFM); P < 0.05] and rates of CHO oxidation [37.2 (2.8) vs 
      24.1 (3.9) mmol.125 min-1 kg FFM-1; P < 0.05]. An increased reliance on CHO 
      metabolism with CHO ingestion was associated with a decrease in fat oxidation. 
      Whereas the contribution from fat oxidation to energy production increased to 51 
      (10)% with glucose infusion, it only reached 18 (4)% with glucose ingestion (P < 
      0.05).(ABSTRACT TRUNCATED AT 250 WORDS)
FAU - Hawley, J A
AU  - Hawley JA
AD  - Department of Physiology, University of Cape Town Medical School, South Africa.
FAU - Bosch, A N
AU  - Bosch AN
FAU - Weltan, S M
AU  - Weltan SM
FAU - Dennis, S C
AU  - Dennis SC
FAU - Noakes, T D
AU  - Noakes TD
LA  - eng
PT  - Comparative Study
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PL  - Germany
TA  - Eur J Appl Physiol Occup Physiol
JT  - European journal of applied physiology and occupational physiology
JID - 0410266
RN  - 0 (Blood Glucose)
RN  - 0 (Fats)
RN  - 0 (Insulin)
RN  - EC 1.1.3.4 (Glucose Oxidase)
RN  - IY9XDZ35W2 (Glucose)
SB  - IM
MH  - Administration, Oral
MH  - Adult
MH  - Blood Gas Analysis
MH  - Blood Glucose/metabolism
MH  - Carbohydrate Metabolism
MH  - Exercise Test
MH  - Fats/metabolism
MH  - Glucose/*administration & dosage/*metabolism
MH  - Glucose Oxidase/blood
MH  - Humans
MH  - Infusions, Intravenous
MH  - Insulin/blood
MH  - Oxidation-Reduction
MH  - Oxygen Consumption
MH  - Physical Exertion/*physiology
EDAT- 1994/01/01 00:00
MHDA- 1994/01/01 00:01
CRDT- 1994/01/01 00:00
PHST- 1994/01/01 00:00 [pubmed]
PHST- 1994/01/01 00:01 [medline]
PHST- 1994/01/01 00:00 [entrez]
AID - 10.1007/BF00843733 [doi]
PST - ppublish
SO  - Eur J Appl Physiol Occup Physiol. 1994;68(5):381-9. doi: 10.1007/BF00843733.