GLYCOGEN METABOLISM AND POST-EXERCISE KETOSIS IN CARBOHYDRATE-RESTRICTED TRAINED AND UNTRAINED RATS

• Published in: Experimental physiology 1989-01, Vol.74 (1), p.27-34
• Main Authors: Adams, J. H., Koeslag, J. H.
• Format: Article
• Language: English
• Subjects: 3-Hydroxybutyric Acid; Animals; Biological and medical sciences; Dietary Carbohydrates; Fundamental and applied biological sciences. Psychology; Glycogen - metabolism; Hydroxybutyrates - blood; Ketosis - etiology; Liver Glycogen - metabolism; Male; Muscles - metabolism; Physical Conditioning, Animal; Physical Exertion; Rats; Space life sciences; Vertebrates: body movement. Posture. Locomotion. Flight. Swimming. Physical exercise. Rest. Sports
• ISSN: 0958-0670; 0144-8757; 1469-445X
• DOI: 10.1113/expphysiol.1989.sp003236

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.