ABSTRACT
In a comparative study, we investigated the effects of maximal eccentric or concentric resistance training combined with whey protein or placebo on muscle and tendon hypertrophy. 22 subjects were allocated into either a high-leucine whey protein hydrolysate + carbohydrate group (WHD) or a carbohydrate group (PLA). Subjects completed 12 weeks maximal knee extensor training with one leg using eccentric contractions and the other using concentric contractions. Before and after training cross-sectional area (CSA) of m. quadriceps and patellar tendon CSA was quantified with magnetic resonance imaging and a isometric strength test was used to assess maximal voluntary contraction (MVC) and rate of force development (RFD). Quadriceps CSA increased by 7.3 ± 1.0% (P < 0.001) in WHD and 3.4 ± 0.8% (P < 0.01) in PLA, with a greater increase in WHD compared to PLA (P < 0.01). Proximal patellar tendon CSA increased by 14.9 ± 3.1% (P < 0.001) and 8.1 ± 3.2% (P = 0.054) for WHD and PLA, respectively, with a greater increase in WHD compared to PLA (P < 0.05), with no effect of contraction mode. MVC and RFD increased by 15.6 ± 3.5% (P < 0.001) and 12-63% (P < 0.05), respectively, with no group or contraction mode effects. In conclusion, high-leucine whey protein hydrolysate augments muscle and tendon hypertrophy following 12 weeks of resistance training - irrespective of contraction mode.
Subject(s)
Milk Proteins , Patellar Ligament/anatomy & histology , Protein Hydrolysates , Quadriceps Muscle/anatomy & histology , Resistance Training/methods , Dietary Carbohydrates , Dietary Supplements , Double-Blind Method , Electromyography , Exercise/physiology , Humans , Hypertrophy , Leucine/administration & dosage , Magnetic Resonance Imaging , Male , Muscle Contraction/physiology , Muscle Strength , Quadriceps Muscle/physiology , Whey Proteins , Young AdultABSTRACT
We have investigated the transcriptional control elements of the human interferon (IFN)-gamma-induced tryptophanyl-tRNA synthetase (hWRS) gene and characterized the transcripts. Transcription leads to a series of mRNAs with different combinations of the first exons. The full-length mRNA codes for a 55-kDa protein (hWRS), but a mRNA lacking exon II is present in almost as high amounts as the full-length transcript. This alternatively spliced mRNA is probably translated into a 48-kDa protein starting from Met48 in exon III. The predicted 48-kDa protein corresponds exactly to an IFN-gamma-inducible protein previously detected by two-dimensional gel electrophoresis. By isolation of genomic clones and construction of plasmids containing hWRS promoter fragments fused to the secreted alkaline phosphatase reporter gene we have mapped a promoter region essential for IFN-mediated gene activation. This region contains IFN-stimulated response elements (ISRE) as well as a Y-box and a gamma-activated sequence (GAS) element. IFN-gamma inducibility of hWRS depends on ongoing protein synthesis, suggesting that so far undescribed transcription factors apart from the latent GAS-binding protein p91 contribute to gene activation. This could be interferon-regulatory factor-1, which binds ISRE elements.
