SOME ASPECTS OF TESTOSTERONE DETERMINATION IN PHYSICALLY ACTIVE PERSONS
Journal Title: Medycyna Sportowa - Year 2007, Vol 23, Issue 6
Abstract
Testosterone is a steroid male sex hormone, produced by testicular Leydig cells, although small amounts are also secreted by the adrenal cortex. The main form of this hormone is protein-bound testosterone. Only 1-2% of testosterone is a free, biologically active testosterone (fT). Testosterone unbound to sex hormone binding globulin (SHBG) is defined as bioavailable testosterone (BAT) and contains fT as well as albumin-bound testosterone. The concentration of this hormone varies during the circadian rhythm. It has been proven that exercise type may have an effect on basal levels of testosterone, which are lower in endurance sportsmen compared to those performing strength and quickness training. Serum levels of this hormone in endurance athletes are lower than in other sportsmen. Testosterone plays a key role in metabolism regulation during physical exercise because of its anabolic and anticatabolic functions. Testosterone improves synthesis of glycogen and proteins and protects them from degradation. Deficiency of testosterone and other hormones, which are often measured in physically active subjects, i. e. cortisol, may result in decreased adaptation to exercise in endurance athletes and reduce physical exercise tolerance. The concentration of testosterone is one of the most frequently determined parameters in sports medicine. The methodological aspects of testosterone determination however, are often not considered. The „golden mean” of free testosterone measurement is equilibrium dialysis, but ammonium sulfate precipitation assay is the reference method for BAT levels assessment. Both methods have some limitations, therefore they are not suitable for routine clinical practice. Moreover, less expensive and more simple direct immunoassays for free testosterone determination have also some disadvantages, i.e. the analytic is not purified prior to its quantification. Interestingly, calculated fT and BAT levels have been found to be nearly identical with corresponding values determined by reference methods (equilibrium dialysis and ammonium sulfate precipitation assay).
Authors and Affiliations
Barbara Mroczko, Marek Mędraś
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