The effects of post-exercise glucose and alanine ingestion on plasma carnitine and ketosis in humans.
AUTOR(ES)
Carlin, J I
RESUMO
1. Several studies have hypothesized that alanine decreases plasma ketone body levels by increasing availability of oxaloacetate, thus allowing acetyl groups to enter the tricarboxylic acid cycle and releasing co-enzyme A (CoA). 2. Four, fasted adult males exercised at 50% of their maximal oxygen consumption for 1.5 h, then ingested 100 g of either glucose or alanine 2 h into recovery. 3. Post-exercise ketosis had developed at 2 h into recovery, as shown by a significantly elevated concentration of beta-hydroxybutyrate in the plasma. At this time plasma free fatty acids were elevated above resting levels while plasma free carnitine concentrations had fallen below resting values. 4. After either alanine or glucose ingestion beta-hydroxybutyrate concentrations fell to the same extent. After the alanine load free carnitine increased above that seen in the glucose trial. Following either alanine or glucose ingestion free fatty acid levels fell; they remained at resting levels in the alanine trial but decreased below rest in the glucose trial. 5. We assume that plasma carnitine concentrations largely reflect the hepatic carnitine pools; therefore, elevations in the plasma free carnitine are probably the result of an increased utilization of acetyl CoA. The significant elevation in plasma free carnitine concentration found after alanine ingestion is consistent with the hypothesis that alanine increases the oxidation of acetyl CoA by providing oxaloacetate for the tricarboxylic acid cycle.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1192181Documentos Relacionados
- Post-exercise ketosis in post-prandial exercise: effect of glucose and alanine ingestion in humans.
- The influence of thermoregulatory mechanisms on post-exercise hypotension in humans.
- Carbohydrate homeostasis and post-exercise ketosis in trained and untrained rats.
- The effects of alanine, glucose and starch ingestion on the ketosis produced by exercise and by starvation.
- The influence of thermal factors on post-exercise haemodynamics in endurance exercise-trained men