Effect of exercise intensities on free fatty acid uptake in whole-body organs measured with 123I-BMIPP-SPECT

Koji Kitada, Kazuo Kubota, Ryoichi Nagatomi, Masatoshi Itoh, Manabu Tashiro, Hiroshi Fukuda, Mehedi Masud, Toshihiko Fujimoto

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)

Abstract

Our purpose was to evaluate the effects of exercise intensities on free fatty acid (FFA) uptake in skeletal muscles, myocardium and liver among humans using 123I-labeled 15-(p-iodophenyl)-3-(R,S)-methyl- pentadecanoic acid (123I-BMIPP) and single photon emission computed tomography technique (SPECT). Six untrained male subjects were studied after 35 min of ergometer bicycle exercise at 40, 70 and 80% maximal aerobic power V̇O2 One subject was studied as resting control. SPECT scan was done 40 min after 123I-BMIPP injection. Mean fractional uptake (FU) in quadriceps femoris muscle (QF) were 0.029 ± 0.001, 0.029 ± 0.002 and 0.025 ± 0.002% at 40, 70 and 80% V̇O2 respectively. FU of QF at 40 and 70% V̇O2 were significantly higher than those of 80% V̇O2 Mean FU into myocardium were 0.048 ± 0.002, 0.052 ± 0.004 and 0.050 ± 0.003% and those in liver were 0.033 ± 0.002, 0.032 ± 0.002 and 0.034 ± 0.003% at each loads, respectively. Any significant changes were not suggestive in liver and myocardium after exercise. Mean FU (the mean values of all exercise intensity) at exercise is 2.86, 0.96 and 0.71 times higher than those at rest in QF, myocardium and liver. These results suggest: (1) in skeletal muscles, energy requirements at above lactate threshold at high exercise intensity predominantly depend upon other intramuscular energy substrates, (2) there is possibility of energy compensation by other substrates in myocardium at higher exercise intensity, (3) FFA uptake in liver might decrease after exercise; however, the influence of exercise intensities is not suggested.

Original languageEnglish
Pages (from-to)769-775
Number of pages7
JournalEuropean Journal of Applied Physiology
Volume104
Issue number5
DOIs
Publication statusPublished - 2008

Keywords

  • Exercise intensity
  • FFA uptake
  • Liver
  • Myocardium
  • SPECT technique
  • Skeletal muscle

ASJC Scopus subject areas

  • Orthopedics and Sports Medicine
  • Public Health, Environmental and Occupational Health
  • Physiology (medical)

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