High dose of whey protein following resistance exercise promotes 45S pre-ribosomal RNA synthesis in older men

Resistance exercise (RE) is a potent stimulator of skeletal muscle hypertrophy among the elderly, however older individuals show a attenuated muscle mass gains in comparison to younger individuals. The mechanisms for this reduced anabolic responsiveness to RE in the elderly are not well defined but may involve suppressed protein synthesis. Moreover, the potential value of protein/amino acids supplementation has been demonstrated. Protein supplementation, specifically whey protein and the essential amino acids such as leucine, has been shown to potentiate the effects of a single bout of RE, which occurs by activating mammalian target of rapamycin (mTOR) pathway. In addition to the effect of RE on translational efficiency (i.e., translational rates per ribosome), recent data have shown that RE increases translation capacity (i.e., total pool of ribosomes) driven by ribosome biogenesis. The synthesis of new ribosomes requires the transcription and accumulation of ribosomal RNA (rRNA) via the assembly of the preinitiation complex (PIC) at the rDNA promoter for 45S pre-rRNA synthesis. Whilst it is well established that protein ingestion following RE further enhances translational efficiency, as yet no study has analysed the effects of protein ingestion following RE on translational capacity. The aim of the present study was to analyse whether whey protein supplementation following a bout of RE can increase pre-rRNA synthesis in the elderly.