A1 Vertaisarvioitu alkuperäisartikkeli tieteellisessä lehdessä
Effects of adenosine, exercise, and moderate acute hypoxia on energy substrate utilization of human skeletal muscle
Tekijät: Heinonen I, Kemppainen J, Kaskinoro K, Peltonen JE, Sipila HT, Nuutila P, Knuuti J, Boushel R, Kalliokoski KK
Kustantaja: AMER PHYSIOLOGICAL SOC
Julkaisuvuosi: 2012
Journal: AJP - Regulatory, Integrative and Comparative Physiology
Tietokannassa oleva lehden nimi: AMERICAN JOURNAL OF PHYSIOLOGY-REGULATORY INTEGRATIVE AND COMPARATIVE PHYSIOLOGY
Lehden akronyymi: Am.J.Physiol Regul.Integr.Comp Physiol
Numero sarjassa: 3
Vuosikerta: 302
Numero: 3
Aloitussivu: R385
Lopetussivu: R390
Sivujen määrä: 6
ISSN: 0363-6119
DOI: https://doi.org/10.1152/ajpregu.00245.2011
Verkko-osoite: PM:22129615
Glucose metabolism increases in hypoxia and can be influenced by endogenous adenosine, but the role of adenosine for regulating glucose metabolism at rest or during exercise in hypoxia has not been elucidated in humans. We studied the effects of exogenous adenosine on human skeletal muscle glucose uptake and other blood energy substrates [free fatty acid (FFA) and lactate] by infusing adenosine into the femoral artery in nine healthy young men. The role of endogenous adenosine was studied by intra-arterial adenosine receptor inhibition (aminophylline) during dynamic one-leg knee extension exercise in normoxia and acute hypoxia corresponding to approximately 3,400 m of altitude. Extraction and release of energy substrates were studied by arterial-to-venous (A-V) blood samples, and total uptake or release was determined by the product of A-V differences and muscle nutritive perfusion measured by positron emission tomography. The results showed that glucose uptake increased from a baseline value of 0.2 +/- 0.2 to 2.0 +/- 2.2 mumol.100 g(-1).min(-1) during adenosine infusion (P < 0.05) at rest. Although acute hypoxia enhanced arterial FFA levels, it did not affect muscle substrate utilization at rest. During exercise, glucose uptake was higher (195%) during acute hypoxia compared with normoxia (P = 0.058), and aminophylline had no effect on energy substrate utilization during exercise, despite that arterial FFA levels were increased. In conclusion, exogenous adenosine at rest and acute moderate hypoxia during low-intensity knee-extension exercise increases skeletal muscle glucose uptake, but the increase in hypoxia appears not to be mediated by adenosine
