Glycogen Metabolism and Post‐exercise Ketosis in Carbohydrate‐restricted Trained and Untrained Rats

Adams, J H; Koeslag, J. H.

doi:10.1113/expphysiol.1989.sp003236

Cited by 8 publications

(11 citation statements)

References 17 publications

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“…The present results confirm previous reports than overnight-rested trained animals store more liver and muscle glycogen than untrained animals do (Baldwin, Fitts, Booth, Winder & Holloszy, 1975;Galbo, Richter, Christensen & Holst, 1975;Winder, Holman & Garhart, 1981;Adams & Koeslag, 1989). Since both groups of animals used approximately the same amount of liver and muscle glycogen during exercise (which was of exactly the same intensity and duration for both) the immediate post-exercise tissue glycogen concentrations were between 35 and 55 % higher in the trained than in the untrained rats (Figs 2 and 3).…”

Section: Discussionsupporting

confidence: 91%

“…after exercise in untrained animals) the latter can in fact continue to be plundered while, in the same hormonal milieu, glycogen is actively being laid down in the muscles (Figs 2 and 3). This even occurs, though to a lesser extent, in carbohydrate-starved untrained rats challenged with exactly the same exercise as the present animals (Adams & Koeslag, 1989). Teleologically, this makes good sense, since a glycogen-depleted liver produces 459 only minor handicaps under normal circumstances, whereas a glycogen-depleted muscle is almost functionless.…”

Section: Discussionmentioning

confidence: 72%

“…The high degree of correlation between the blood ketone body concentration and simultaneous liver glycogen content (r = -0-88) suggests that the link between the two is very close indeed after exercise. Such a close link has never previously been shown to exist between the post-exercise blood ketone body concentration and any other biochemical variable measured to date (Johnson et al 1969 a, b;Johnson & Rennie, 1973;Winder et al 1973;Rennie et al , 1976Holloszy et al 1978;Koeslag et al 1980Koeslag et al , 1982Koeslag et al , 1985Beattie et al 1985;Adams et al 1987;Adams & Koeslag, 1989). The nature of the link, and the mechanisms which drive the system, remain matters for speculation beyond the scope of this article.…”

Section: Discussionmentioning

confidence: 96%

“…We confined our enquiry to the measurement of the blood 3-hydroxybutyrate and tissue glycogen concentrations because we could only obtain very small quantities of blood from each rat with certainty, and because the plasma hormone, glucose, free fatty acid, and acetoacetate concentrations have already been studied exhaustively without leading to clear conclusions (Johnson et al 1969a, b;Johnson, Rennie, Walton & Webster, 1971;Johnson & Walton, 1972;Johnson & Rennie, 1973;Winder et al 1973;Rennie, Winder & Holloszy, 1976;Holloszy, Winder, Fitts & Rennie, 1978;Koeslag, Noakes & Sloan, 1980, 1982Beattie & Winder, 1984Koeslag, Levinrad, Lochner & Sive, 1985;Adams, Irving, Koeslag, Lochner, Sandell & Wilkinson, 1987). The effects of dietary manipulation on the tissue glycogen levels and post-exercise ketosis are described elsewhere (Adams & Koeslag, 1989).…”

mentioning

confidence: 99%

“…The effects of dietary manipulation on the tissue glycogen levels and post-exercise ketosis are described elsewhere (Adams & Koeslag, 1989).…”

Section: Introductionmentioning

confidence: 99%

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Carbohydrate homeostasis and post‐exercise ketosis in trained and untrained rats.

Adams

Koeslag

1988

The Journal of Physiology

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SUMMARY1. Experiments were carried out to establish what relationship there is between the concentration of ketone bodies in the blood and the concentrations of glycogen in muscle and liver of thirty-six trained and thirty-six untrained rats exercised at the same absolute load. There were, in addition. non-exercised control animals (of which thirty-six were trained and thirty-six untrained) which were studied on the same day.2. Training occurred on a level treadmill at 0 2 m/s for I h/day. 5 days a week, for 6 weeks. The untrained animals ran on the treadmill every 3rd day for 5 min to maintain familiarity with treadmill running without training them.3. At the end of the 6th week, the experimental animals ran for 1 h at 0 2 m/s on a level treadmill. Blood 3-hydroxybutyrate and tissue glycogen concentrations were measured at the beginning and immediately after exercise, and then every 30 min for 2 h.4. Physically trained rats had higher pre-and immediate post-exercise liver glycogen concentrations than untrained rats: 413 + 15 and 300+8,umol/g before exercise in trained and untrained rats respectively, and 225+8 and 166+3 /tmol/g immediately after (P < 0 05). 5. Muscle glycogen, which was also higher in trained than in untrained rats, was resynthesized at approximately the same rate in the two groups of animals (9 and 11 ,tmol/(g h), but the trained animals were able to achieve this without further depletion of liver glycogen beyond that which had occurred during exercise. In untrained animals liver glycogen concentrations continued to drop for 60 mnin beyond the end of exercise.6. The difference between the immediate post-exercise blood concentrations of 3-hydroxybutyrate of trained and untrained animals was not significant. Thereafter the level rose, within 60-90 min, to 1-31+0-04 mmol/l in the untrained animals, but to only 0-62 + 0-05 mmol/l in the trained animals (P < 0 05).7. There was a striking inverse relationship between the blood 3-hydroxybutyrate concentrations of all the animals (trained and untrained) and their simultaneous liver glycogen concentrations during the experiment (r = -0-88; P < 0-001).8. The results suggest that the phenomenon of post-exercise ketosis is associated with an inability to maintain the liver glycogen concentration after exercise.

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Section: Discussionsupporting

confidence: 91%

Section: Discussionmentioning

confidence: 72%

Section: Discussionmentioning

confidence: 96%

mentioning

confidence: 99%

“…The effects of dietary manipulation on the tissue glycogen levels and post-exercise ketosis are described elsewhere (Adams & Koeslag, 1989).…”

Section: Introductionmentioning

confidence: 99%

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Carbohydrate homeostasis and post‐exercise ketosis in trained and untrained rats.

Adams

Koeslag

1988

The Journal of Physiology

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Post-exercise ketosis and the glycogen content of liver and muscle in rats on a high carbohydrate diet

Adams

Koeslag

1989

Europ. J. Appl. Physiol.

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Post-exercise ketosis is known to be suppressed by physical training and by a high carbohydrate diet. As a result it has often been presumed, but not proven, that the development of post-exercise ketosis is closely related to the glycogen content of the liver. We therefore studied the effect of 1 h of treadmill running on the blood 3-hydroxybutyrate and liver and muscle glycogen concentrations of carbohydrate-loaded trained (n = 72) and untrained rats (n = 72). Resting liver and muscle glycogen levels were 25%-30% higher in the trained than in the untrained animals. The resting 3-hydroxybutyrate concentrations of both groups of rats were very low: less than 0.08 mmol.l-1. Exercise did not significantly influence the blood 3-hydroxybutyrate concentrations of trained rats, but caused a marked post-exercise ketosis (1.40 +/- 0.40 mmol.l-1 h after exercise) in the untrained animals, the time-course of which was the approximate inverse of the changes in liver glycogen concentration. Interpreting the results in the light of similar data obtained after a normal and low carbohydrate diet it has been concluded that trained animals probably owe their relative resistance to post-exercise ketosis to their higher liver glycogen concentrations as well as to greater peripheral stores of mobilizable carbohydrate.

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Exogenous Ketone Supplements in Athletic Contexts: Past, Present, and Future

Evans

McClure²,

Koutnik³

et al. 2022

Sports Med

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The ketone bodies acetoacetate (AcAc) and β-hydroxybutyrate (βHB) have pleiotropic effects in multiple organs including brain, heart, and skeletal muscle by serving as an alternative substrate for energy provision, and by modulating inflammation, oxidative stress, catabolic processes, and gene expression. Of particular relevance to athletes are the metabolic actions of ketone bodies to alter substrate utilisation through attenuating glucose utilisation in peripheral tissues, anti-lipolytic effects on adipose tissue, and attenuation of proteolysis in skeletal muscle. There has been long-standing interest in the development of ingestible forms of ketone bodies that has recently resulted in the commercial availability of exogenous ketone supplements (EKS). These supplements in the form of ketone salts and ketone esters, in addition to ketogenic compounds such as 1,3-butanediol and medium chain triglycerides, facilitate an acute transient increase in circulating AcAc and βHB concentrations, which has been termed ‘acute nutritional ketosis’ or ‘intermittent exogenous ketosis’. Some studies have suggested beneficial effects of EKS to endurance performance, recovery, and overreaching, although many studies have failed to observe benefits of acute nutritional ketosis on performance or recovery. The present review explores the rationale and historical development of EKS, the mechanistic basis for their proposed effects, both positive and negative, and evidence to date for their effects on exercise performance and recovery outcomes before concluding with a discussion of methodological considerations and future directions in this field.

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Glycogen Metabolism and Post‐exercise Ketosis in Carbohydrate‐restricted Trained and Untrained Rats

Cited by 8 publications

References 17 publications

Carbohydrate homeostasis and post‐exercise ketosis in trained and untrained rats.

Carbohydrate homeostasis and post‐exercise ketosis in trained and untrained rats.

Post-exercise ketosis and the glycogen content of liver and muscle in rats on a high carbohydrate diet

Exogenous Ketone Supplements in Athletic Contexts: Past, Present, and Future

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