Skeletal muscle pyruvate dehydrogenase activity during acetate infusion in humans
| Autor: | E. Hultman, L. L. Spriet, C. T. Putman, George J. F. Heigenhauser, D. J. Dyck |
|---|---|
| Rok vydání: | 1995 |
| Předmět: |
Adult
Male medicine.medical_specialty Physiology Endocrinology Diabetes and Metabolism Pyruvate Dehydrogenase Complex Acetates Pyruvate dehydrogenase activity chemistry.chemical_compound Oxygen Consumption Acetyl Coenzyme A Physiology (medical) Internal medicine Mole medicine Humans Coenzyme A Infusions Intravenous Muscle Skeletal Acetylcarnitine Sodium bicarbonate Glycogen Skeletal muscle Hydrogen-Ion Concentration Pyruvate dehydrogenase complex Blood Endocrinology medicine.anatomical_structure chemistry Female Sodium acetate medicine.drug |
| Zdroj: | American Journal of Physiology-Endocrinology and Metabolism. 268:E1007-E1017 |
| ISSN: | 1522-1555 0193-1849 |
| DOI: | 10.1152/ajpendo.1995.268.5.e1007 |
| Popis: | Pyruvate dehydrogenase activity (PDHa), acetyl group, and citrate accumulation were examined in human skeletal muscle at rest and during cycling exercise while acetate was infused. Eight subjects received 400 mmol of sodium acetate (Ace) at a constant rate during 20 min of rest, 5 min of cycling at 40% maximal O2 uptake (VO2max) and 15 min of cycling at 80% VO2max. Two weeks later experiments were repeated while 400 mmol of sodium bicarbonate was infused in the control condition (CON). Ace infusion increased muscle acetyl-coenzyme A (acetyl-CoA), citrate, and acetylcarnitine. A decline in resting PDHa during 20 min of Ace infusion (0.37 +/- 0.08 vs. 0.16 +/- 0.03 mmol.min-1.kg wet wt-1) coincided with an elevation in the acetyl-CoA-to-free CoA ratio (acetyl-CoA/CoASH; 0.28 +/- 0.04 to 0.73 +/- 0.14). After 20 min of CON infusion, resting PDHa (0.32 +/- 0.06 mmol.min-1.kg wet wt-1) was similar to PDHa before Ace infusion. During exercise, acetyl-CoA, citrate, and acetyl-CoA/CoASH were further elevated, and the differences that existed at rest were resolved. PDHa increased to the same extent in Ace and CON, in which it was 44-47% transformed after 5 min at 40% VO2max and completely transformed after 15 min at 80% VO2max. At rest PDHa was regulated by variations in acetyl-CoA/CoASH secondary to enhanced acetate metabolism. Conversely, during exercise PDHa regulation appeared independent of variations in acetyl-CoA/CoASH. The resting data are consistent with a central role for PDHa and citrate in the regulation of the glucose-fatty acid cycle in skeletal muscle, as classically proposed. However, in the present study Ace infusion was not effective in perturbing the glucose-fatty acid cycle during exercise. |
| Databáze: | OpenAIRE |
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