PMID- 1483439
OWN - NLM
STAT- MEDLINE
DCOM- 19930216
LR  - 20190827
IS  - 0301-5548 (Print)
IS  - 0301-5548 (Linking)
VI  - 65
IP  - 6
DP  - 1992
TI  - Effects of carbohydrate feedings on plasma free tryptophan and branched-chain 
      amino acids during prolonged cycling.
PG  - 513-9
AB  - Brain serotonin (5-hydroxytryptamine, 5-HT) has been suggested to be involved in 
      central fatigue during prolonged exercise. Changes in the ratio of plasma free 
      tryptophan (free Trp) to branched-chain amino acids (BCAA) are associated with 
      altered brain 5-HT synthesis. The purposes of this study were to describe 
      systematically the effects of prolonged exercise on changes in plasma free Trp 
      and BCAA and to examine the effects of carbohydrate (CHO) feedings on these same 
      variables. Eight well-trained men [VO2max = 57.8 (SE 4.1) ml kg-1 min-1] cycled 
      for up to 255 min at a power output corresponding to VO2 at lactate threshold 
      (approximately 68% VO2max) on three occasions separated by at least 1 week. 
      Subjects drank 5 ml kg-1 body wt-1 of either a water placebo, or a liquid 
      beverage containing a moderate (6% CHO) or high (12% CHO) concentration of 
      carbohydrate beginning at min 14 of exercise and every 30 min thereafter. 
      Exercise time to fatigue was shorter in subjects receiving placebo [190 (SE 4) 
      min] as compared to 6% CHO [235 (SE 10) min] and 12% CHO [234 (SE 9) min] (P < 
      0.05). Glucose and insulin decreased in the placebo group, and free Trp, 
      free-Trp/BCAA, and free fatty acids increased approximately five- to sevenfold (P 
      < 0.05). These changes were attenuated in a dose-related manner by the 
      carbohydrate drinks.(ABSTRACT TRUNCATED AT 250 WORDS)
FAU - Davis, J M
AU  - Davis JM
AD  - Department of Exercise Science, School of Public Health, University of South 
      Carolina, Columbia 29208.
FAU - Bailey, S P
AU  - Bailey SP
FAU - Woods, J A
AU  - Woods JA
FAU - Galiano, F J
AU  - Galiano FJ
FAU - Hamilton, M T
AU  - Hamilton MT
FAU - Bartoli, W P
AU  - Bartoli WP
LA  - eng
PT  - Clinical Trial
PT  - Controlled Clinical Trial
PT  - Journal Article
PL  - Germany
TA  - Eur J Appl Physiol Occup Physiol
JT  - European journal of applied physiology and occupational physiology
JID - 0410266
RN  - 0 (Amino Acids, Branched-Chain)
RN  - 0 (Blood Glucose)
RN  - 0 (Dietary Carbohydrates)
RN  - 0 (Fatty Acids, Nonesterified)
RN  - 0 (Insulin)
RN  - 0 (Lactates)
RN  - 8DUH1N11BX (Tryptophan)
SB  - IM
MH  - Adult
MH  - Amino Acids, Branched-Chain/*blood
MH  - *Bicycling
MH  - Blood Glucose/metabolism
MH  - Body Temperature/physiology
MH  - Dietary Carbohydrates/*pharmacology
MH  - Dose-Response Relationship, Drug
MH  - Exercise/*physiology
MH  - Exercise Test
MH  - Fatty Acids, Nonesterified/blood
MH  - Heart Rate/physiology
MH  - Humans
MH  - Insulin/blood
MH  - Lactates/blood
MH  - Male
MH  - Oxygen Consumption/physiology
MH  - Pulmonary Gas Exchange/physiology
MH  - Tryptophan/*blood
EDAT- 1992/01/01 00:00
MHDA- 1992/01/01 00:01
CRDT- 1992/01/01 00:00
PHST- 1992/01/01 00:00 [pubmed]
PHST- 1992/01/01 00:01 [medline]
PHST- 1992/01/01 00:00 [entrez]
AID - 10.1007/BF00602357 [doi]
PST - ppublish
SO  - Eur J Appl Physiol Occup Physiol. 1992;65(6):513-9. doi: 10.1007/BF00602357.