How UCP3 expression is affected during longer periods of low carbohydrate availability remain to be seen. Acute
changes in mRNA expression must be interpreted with caution, since protein amounts as the result of chronic adaptation were learn more not the focus of this study. For the other genes investigated, this study is consistent with previous literature which shows that the expression of GLUT4 [22] and PGC-1α mRNA is elevated following exercise [6, 17, 18]. More surprisingly, exercise stimulated GSK126 clinical trial increases in mRNA were not seen in MFN2, as these have previously been shown to be sensitive to exercise [8, 12, 14, 21, 47]. We confirmed in this study that our housekeeping gene was insensitive to both heat and exercise, and this is supported in the literature [12, 31, 32]. Therefore, it remains unknown
why an exercise induced increase in MFN2 was not observed in the current study. MFN2 is a mitochondrial membrane protein involved in the fusion events of the mitochondrial architecture [21]. Increased expression of this gene is thought to lead to greater mitochondrial function through matrix protein mixing [48]. One of our previous investigations showed robust (~50%) increases in MFN2 following 5 hr of cycling, suggesting that greater exercise Seliciclib research buy intensity or duration may be needed for up regulation of this gene [8]. However, in another investigation from our lab, 1 hr of cycling at 60% of maximum workload increased MFN2 expression (~20%) [12]. In the current study the exercise protocol (1 hr at 70% maximum workload) should have been sufficient to increase MFN2 gene expression. Due to the design of this study it is not apparent whether this is due to the modest stress of the exercise bout, modest changes in individual variability in a somewhat Fluorometholone Acetate small sample size, or an attenuating effect of the hot environment. We previously showed that MFN2 is not significantly affected by exercise in varying environmental temperatures, with similar exercise responses in the heat (33°C),
cold (7°C), and neutral (20°C) environments [12]. This suggests that small increases in variability with a sample size of eight may have affected the statistical outcome of this particular gene. Despite this, carbohydrate supplementation had no apparent attenuating effects on this mitochondrial fusion gene. To our knowledge this is the first time MFN2 has been investigated following carbohydrate supplementation in humans. Conclusions These data contribute to the general understanding of stimuli regulating metabolic adaptation following exercise. We found that exercise and recovery in the heat stimulates genes for PGC-1α, UCP3 and GLUT4. Carbohydrate ingestion during exercise and recovery in a hot environment attenuated mRNA expression of UCP3, but had no effect on the expression of MFN2, GLUT4 and PGC-1α.