We sought to determine whether acute resistance exercise (RE)-induced gene expression is modified by RE training. We studied the expression patterns of a select group of genes following an acute bout of RE in naïve and hypertrophying muscle. Thirteen untrained subjects underwent supervised RE training for 12 wk of the nondominant arm and performed an acute bout of RE 1 wk after the last bout of the training program (training+acute). The dominant arm was either unexercised (control) or subjected to the same acute exercise bout as the trained arm (acute RE). Following training, men (14.8 ± 2.8%; P < 0.05) and women (12.6 ± 2.4%; P < 0.05) underwent muscle hypertrophy with increases in dynamic strength in the trained arm (48.2 ± 5.4% and 72.1 ± 9.1%, respectively; P < 0.01). RE training resulted in attenuated anabolic signaling as reflected by a reduction in rpS6 phosphorylation following acute RE. Changes in mRNA levels of genes involved in hypertrophic growth, protein degradation, angiogenesis, and metabolism commonly expressed in both men and women was determined 4 h following acute RE. We show that RE training can modify acute RE-induced gene expression in a divergent and gene-specific manner even in genes belonging to the same ontology. Changes in gene expression following acute RE are multidimensional, and may not necessarily reflect the actual adaptive response taking place during the training process. Thus RE training can selectively modify the acute response to RE, thereby challenging the use of gene expression as a marker of exercise-induced adaptations.
Keywords: gene expression; hypertrophy; resistance exercise; skeletal muscle; training.