The expression of androgen receptors in human neck and limb muscles: effects of training and self-administration of androgenic-anabolic steroids

The purpose of this study was to investigate the immunohistochemical expres sion of androgen receptors (AR) in human vastus lateralis and trapezius mus cles and to determine whether long-term strength training and self-administ ration of androgenic-anabolic steroids are accompanied by changes in AR con tent. Biopsy samples were taken from eight high-level power-lifters (P), ni ne high-level power-lifters who used anabolic steroids (PAS) and six untrai ned subjects (U). Myonuclei and AR were visualised in cross-sections staine d with the monoclonal antibody against AR and 4', 6-diamidino-2-phenylindol e. The proportion of AR-containing myonuclei per fibre cross-section was hi gher in the trapezius than in the vastus lateralis (P<0.05). In the trapezi us, the proportion of AR-containing myonuclei was higher in P compared to U and in PAS compared to both P and U (P<0.05). On the contrary, in the vast us lateralis, there were no differences in AR content between the three gro ups. Myonuclear number in both muscles was higher in P compared to U and in PAS compared to both P and U (P<0.05). In conclusion, AR content differs g reatly between human neck and limb muscles. Moreover, the regulation of AR- containing myonuclei following training and self-administration of androgen ic-anabolic steroids is muscle dependent.