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GLYCOGEN METABOLISM AND POST‐EXERCISE KETOSIS IN CARBOHYDRATE‐RESTRICTED TRAINED AND UNTRAINED RATS
Author(s) -
Adams J. H.,
Koeslag J. H.
Publication year - 1989
Publication title -
quarterly journal of experimental physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.925
H-Index - 101
eISSN - 1469-445X
pISSN - 0144-8757
DOI - 10.1113/expphysiol.1989.sp003236
Subject(s) - glycogen , medicine , endocrinology , carbohydrate , ketosis , carbohydrate metabolism , treadmill , chemistry , biology , diabetes mellitus
Liver and muscle glycogen, and blood 3‐hydroxybutyrate concentrations were studied during and for 2 h after treadmill running for 1 h, in 144 carbohydrate‐starved trained and untrained rats. The resting liver glycogen concentration of the trained animals was 227 ± 8 (mean ± S.E.M.) µmol glucosyl units/g wet mass, compared with 162 ± 12 µmol/g in the untrained animals. The muscle glycogen levels were 42 ± 1 and 28 ± 1 µmol/g respectively. Exercise reduced muscle and liver glycogen concentrations by approximately the same absolute amounts in both animal groups, leaving the trained rats with nearly 3 times as much residual glycogen as the untrained animals. There was very little resynthesis of muscle glycogen recovery, but the trained animals replenished approximately 43% of the liver glycogen used during exercise. The blood 3‐hydroxybutyrate concentrations were negatively correlated with the simultaneous liver glycogen concentration of our experimental animals ( r = −0·55; P 〈 0·001). It is concluded that trained animals primarily owe their resistance to post‐exercise ketosis to their large stores of glycogen.