(99m)Tc-sestamibi uptake in rat skeletal muscle and heart: physiological determinants and correlations.

The lipophilic cationic radiotracer (99m)Tc-sestamibi, known to be concentrated within mitochondria, is widely used for myocardial perfusion and to a lesser extent for muscle metabolism imaging. However, the exact distribution pattern in skeletal muscle has not been yet studied in detail. The present study aims to investigate the (99m)Tc-sestamibi uptake in rat skeletal muscle and myocardium in relation to their metabolic characteristics.

Effect of aerobic training on 99mTc-methoxy isobutyl isonitrile (99mTc-sestamibi) uptake by myocardium and skeletal muscle: implication for noninvasive assessment of muscle metabolic profile.

Aim: The effect of long-term endurance training on skeletal muscle and myocardial uptake of (99m)Tc-sestamibi, a radiopharmaceutical accumulating in the mitochondria, was investigated.

Methods: Twenty-six Wistar rats were divided into a trained (5 days week(-1) endurance running for 14 weeks) and an untrained group. On completion of training, (99m)Tc-sestamibi was administered and, 2 h post-injection, the myocardium and the soleus, extensor digitorum longus (EDL) and medial gastrocnemius (MG) muscles were removed for the measurement of cytochrome c oxidase (CCO) activity and (99m)Tc-sestamibi uptake.

Assessment of brown adipose tissue activity in rats by 99mTc-sestamibi uptake.

Brown adipose tissue (BAT) physiology and imaging have recently attracted considerable attention. BAT is characterized both by enhanced perfusion and increased mitochondrial activity. (99m)Tc-sestamibi is a lipophilic cationic tracer that concentrates in mitochondria.