Skeletal muscle mitochondrial volume and myozenin-1 protein differences exist between high versus low anabolic responders to resistance training
Year: 2018
Type: preprint
Abstract: Background . We sought to examine how 12 weeks of resistance exercise training (RET) affected skeletal muscle myofibrillar and sarcoplasmic protein levels along with markers of mitochondrial physiology in high versus low anabolic responders. Methods . Untrained college-aged males were classified as anabolic responders in the top 25 th percentile [HI; n=13, dual x-ray absorptiometry total body muscle mass change (Δ) =+3.1±0.3 kg, Δ vastus lateralis (VL) thickness =+0.59±0.05 cm, Δ muscle fiber CSA =+1426±253 μm 2 ) and bottom 25 th percentile (LO; n=12, +1.1±0.2 kg, +0.24±0.07 cm, +5±209 μm 2 ; p<0.001 for all Δ scores compared to HI]. VL muscle prior to (PRE) and following RET (POST) was assayed for myofibrillar and sarcoplasmic protein concentrations, myosin and actin protein content, and markers of mitochondrial volume. Myofibrillar protein levels of genes related to new myofibril formation as well as whole lysate PGC1-α protein levels were also assessed. Results . Main effects of cluster (HI>LO, p=0.018, Cohen’s d=0.737) and time (PRE>POST, p=0.037, Cohen’s d=-0.589) were observed for citrate synthase activity, although no significant interaction existed. POST myofibrillar myozenin-1 protein levels were up-regulated in the LO cluster (+25%, p=0.025, Cohen’s d = 0.691). No interactions or main effects existed for other assayed markers. Our data suggest myofibrillar or sarcoplasmic protein concentrations do not differ between HI versus LO anabolic responders prior to or following a 12-week RET program. Discussion . Greater mitochondrial volume in HI responders may have facilitated greater anabolism, and myofibril myozenin-1 protein levels may represent a biomarker that differentiates anabolic responses to RET. However, mechanistic research validating these hypotheses is needed.
Institution: Auburn University
Language: English
Subfield: Cell Biology
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W4234044682