Heavy resistance exercise training and skeletal muscle androgen receptor expression in younger and older men

6533b835fe1ef96bd12a00a9

RESEARCH PRODUCT

Heavy resistance exercise training and skeletal muscle androgen receptor expression in younger and older men

Maarit Lehti William J. Kraemer Juha J. Hulmi Arto Pakarinen Antti A. Mero Markku Alen Jyrki Komulainen Keijo Häkkinen Harri Selänne Juha P. Ahtiainen Vuokko Kovanen Kai Nyman

subject

Adult Male Aging medicine.medical_specialty medicine.drug_class Clinical Biochemistry Physical exercise Biology Biochemistry Muscle hypertrophy Endocrinology Reference Values Internal medicine medicine Humans Testosterone Muscle Strength RNA Messenger Muscle Skeletal ta315 Molecular Biology Testosterone Aged Pharmacology Reverse Transcriptase Polymerase Chain Reaction Gene Expression Profiling Organic Chemistry Skeletal muscle Resistance Training Middle Aged Androgen Androgen receptor Endocrinology medicine.anatomical_structure Gene Expression Regulation Receptors Androgen Ageing Lean body mass

description

Effects of heavy resistance exercise on serum testosterone and skeletal muscle androgen receptor (AR) concentrations were examined before and after a 21-week resistance training period. Seven healthy untrained young adult men (YT) and ten controls (YC) as well as ten older men (OT) and eight controls (OC) volunteered as subjects. Heavy resistance exercise bouts (5 × 10 RM leg presses) were performed before and after the training period. Muscle biopsies were obtained before and 1h and 48 h after the resistance exercise bouts from m.vastus lateralis (VL) to determine cross-sectional area of muscle fibers (fCSA) and AR mRNA expression and protein concentrations. No changes were observed in YC and OC while resistance training led to significant increases in maximal strength of leg extensors (1 RM), fCSA and lean body mass in YT and OT. Acute increases occurred in serum testosterone concentrations due to resistance exercises but basal testosterone remained unaltered. Mean AR mRNA expression and protein concentration remained unchanged after heavy resistance exercise bouts compared to pre-values. The individual pre- to post-training changes in resting (pre-exercise) AR protein concentration correlated with the changes in fCSA and lean body mass in the combined group of YT and OT. Similarly, it correlated with the changes in 1 RM in YT. Although mean AR expression did not changed due to the resistance exercise training, the present findings suggest that the individual changes of AR protein concentration in skeletal muscle following resistance training may have an impact on training-induced muscular adaptations in both younger and older men.

year	journal	country	edition	language
2010-08-12	Steroids

10.1016/j.steroids.2010.10.012 https://doi.org/10.1016/j.steroids.2010.10.012