Increased activity of glycogen synthetase. See
E n d o g e n o u s S t e ro i d
P ro f i l i n g i n t h e
A t h l e t e Bi o l o g i c a l
P a s s p o r t
Pierre-Edouard Sottas, PhD *, Martial Saugy, PhD, PD,
Christophe Saudan, PhD
Endocrinol Metab Clin N Am 39 (2010) 59–73
Anabolic–androgenic steroids (AAS) represent a class of steroidal hormones affiliated
with the hormone testosterone. Testosterone is produced naturally in the human body
and conjugated mainly with glucuronide and sulfate before excretion in urine (phase 2
metabolism). The androgenic effects of testosterone and its prohormones generally
are associated with masculanization and virilization, while its anabolic effects are
associated with protein building in the body. 1 In power sports, exogenous AAS
primarily are used as myotrophic agents to promote muscle mass and strength.
Although their efficacy in terms of improved physical function has been debated
during decades, 1,2 a comprehensive study by Bhasin and colleagues demonstrated
in 1996 that testosterone can act as a performance-enhancing substance when supra-
physiological doses are administered. 3 Exogenous AAS also are known to be used in
endurance sports for improved recovery. Endurance athletes favour low (to limit myo-
trophy) but frequent doses for replacement levels. Indeed, overtraining-induced stress
can upset the balance between anabolic and catabolic states of the hormones of the
endocrine system. Some endurance athletes may find in synthetic AAS an
ergogenic supercompensating agent for sustained testosterone concentrations and, in turn, a performance-enhancing substance to allow more intense training sessions. In addition, it has been shown that testosterone not only plays an important role in muscle metabolism during the regeneration phase after physical exercise, but also seems to increase the ability of the muscle to refill its glycogen storage through an increased activity of the muscle glycogen synthetase.
These two citations describe the it further.
4. Urhausen A, Kindermann W. The endocrine system in overtraining. In: Arren MP,
Constantini NW, editors. Sports endocrinology. Totowa (NJ): Humana Press;
2000. p. 347–70.
5. Gillespie CA, Edgerton VR. The role of testosterone in exercise-induced glycogen
supercompensation. Horm Metab Res 1970;2:364–6