Sports snips
Replacing just one nucleotide in the genes regulating testosterone metabolism affects athletic success and disease risk
Scientists have found out how substitutions of just one nucleotide in genes that affect testosterone levels affect the physical characteristics of athletes. It turned out that combinations of some of them affect the size of muscle fibers, lean mass and strength of a person. Research supported by a grant The Russian Scientific Foundation, will allow in the near future to develop the latest genetic tests that can be applied not only in solving sports problems, but also to identify the risks of developing dangerous diseases. The results of the work are published in the European Journal of Applied Physiology (Guilherme et al., Genomic predictors of testosterone levels are associated with muscle fiber size and strength).
Testosterone is a steroid hormone from the androgen group responsible for sexual functions and the formation of secondary sexual characteristics in men. In addition, it has pronounced anabolic properties, that is, it stimulates tissue growth. The use of testosterone can be indicated for a number of diseases, for example, for elderly men whose hormone levels in the body are low, as well as for men suffering from type 2 diabetes and obesity — in these cases, it increases the susceptibility of tissues to insulin and regulates fat deposition, respectively.
"The natural level of testosterone varies in different people, and in many ways it is determined by heredity. So, in men, genetic factors are responsible for approximately 40-70% of the variability in testosterone levels, and in women — about 65%. In the course of the study, we were able to clarify the relationship between some genetic markers responsible for increased testosterone levels and certain characteristics of muscle fibers," says project manager Eduard Generozov, head of the Laboratory of Human Molecular Genetics at the Federal Research and Clinical Center of Physico-Chemical Medicine of the Federal Medical and Biological Agency.
Researchers together with colleagues from the Russian State University of Physical Culture, Sports, Youth and Tourism, Kazan State Medical University, Plekhanov Russian University of Economics and Liverpool John Moores University studied muscle fiber samples obtained from more than 170 volunteer athletes during biopsy. The participants of the experiment were engaged in different sports (weightlifting, powerlifting, alpine skiing, arm wrestling), respectively, their physical characteristics differed.
To compare the properties of athletes' muscles with their hereditary material, the authors also isolated DNA from venous blood, and then examined it using advanced DNA chip technology. They focused on single nucleotide substitutions (SNPs) in genes that could lead to individual differences in testosterone levels and related characteristics.
The analysis allowed us to determine that five alleles of the DOCK3, ESR1, GLIS3, GRAMD1B and TRAIP genes associated with higher testosterone levels also cause an increase in the thickness of muscle fibers and indicators of lean body weight, grip strength and strength characteristics in general.
"The work is primarily devoted to aspects of the regulation of muscle activity. In addition to the obvious applied significance for sports genetics, understanding these mechanisms is also very important from a medical point of view. There is a large proportion of diseases associated with loss of function of skeletal muscles, for example, senile sarcopenia, as well as hereditary muscular dystrophy. Often these diseases are caused by disorders in the same genes that are normally responsible for the manifestation of athletic qualities. Skeletal muscles account for up to 40-45% of body weight, and the problems of their metabolism are directly related to the development of such formidable diseases as type II diabetes mellitus and metabolic syndrome. For this reason, a study that sheds light on how muscles function normally is of great importance in pathology studies," concluded Eduard Generozov.
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