Muscle metabolism during lactate infusion in human phosphofructokinase deficiency
| Autor: | L. A. Bertocci, Steven F. Lewis, Ronald G. Haller |
|---|---|
| Rok vydání: | 1993 |
| Předmět: |
Adult
Male High-energy phosphate medicine.medical_specialty Magnetic Resonance Spectroscopy Glycogenolysis Adolescent Phosphocreatine Physiology Phosphofructokinase-1 Physical Exertion chemistry.chemical_compound Adenosine Triphosphate Ammonia Physiology (medical) Internal medicine Sodium lactate medicine Humans Glycolysis Infusions Intravenous Muscle fatigue Muscles Phosphorus Isotopes Hydrogen-Ion Concentration Middle Aged medicine.disease Magnetic Resonance Imaging Adenosine Diphosphate Phosphofructokinase deficiency Endocrinology chemistry Lactates Female Phosphofructokinase |
| Zdroj: | Journal of Applied Physiology. 74:1342-1347 |
| ISSN: | 1522-1601 8750-7587 |
| DOI: | 10.1152/jappl.1993.74.3.1342 |
| Popis: | We studied the effect of intravenous infusion of sodium lactate (La) on muscle high-energy phosphate metabolism, pH, and venous effluent [NH3] in three patients with muscle phosphofructokinase (PFK) deficiency and three healthy subjects during maximal-effort rhythmic handgrip exercise (5 s of contraction alternated with 5 s of rest) performed for 3 min. Healthy subjects were matched to PFK-deficient patients for gender and maximal handgrip strength. Force production was recorded and during lactate infusion was matched to that without lactate. 31P-magnetic resonance spectroscopy was used to measure intracellular phosphocreatine (PCr), orthophosphate (Pi), ATP, and pH in the flexor digitorum profundus of the exercising forearm. La infusion had no effect on healthy subjects or patients during rest. In healthy subjects, La infusion had no effect on depletion of PCr; accumulation of Pi, ADP, or venous effluent NH3; or decline in pH in exercising muscle. In contrast, during exercise in PFK-deficient patients, [PCr] was higher (17.9 +/- 1.9 vs. 13.1 +/- 1.4 mmol/kg) and [phosphomonoester] (11.4 +/- 1.3 vs. 6.5 +/- 1.4 mmol/kg), [Pi] (9.2 +/- 1.8 vs. 5.0 +/- 0.7 mmol/kg), [ADP] (60.4 +/- 7.0 vs. 37.9 +/- 9.9 mumol/kg), and venous effluent [NH3] (335 +/- 136 vs. 176 +/- 61 mM) were lower (P < 0.05) during La infusion than in control conditions. The effects of La infusion on intracellular [PCr], [Pi], [phosphomonoester], [ADP], and [NH3] in PFK-deficient patients are consistent with the hypothesis that exogenous La augments the rate of oxidative phosphorylation in active muscle by bypassing the enzymatic block at PFK. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|