ABSTRACT
Anabolic androgenic steroids [AAS] are compounds formed from testosterone or one of its derivatives, which are largely used by amateur and professional athletes to improve the athletic performance. Nandrolone is an anabolic steroid widely used in some sports in which muscle mass and strength are important factors. The aim of this work was to evaluate the effects of nandrolone on skeletal muscle general structure and ultrastucture. Male albino rats were used in this study. They were divided into two groups, control and treated groups. The treated group received i.m. injections of Deca-Durabolin for 10 weeks. At the end of the experiment, the animals were anaesthetized, and blood samples were obtained for determination of both lactate dehydrogenase [LD] and creatine kinase [CK] activity then soleus muscles were removed for light and electron microscopic studies. Nandrolone treatment caused variation in size and shape of muscle fibers. Small atrophic angular fibers next to hypertrophic ones were seen. Muscle fibers were separated with increased connective tissue. Cross sectional area [CSA] of muscle fibers were slightly increased. The mean LD activity was increased and the mean CK activity was markedly increased. In conclusion nandrolone produced hypertrophy of the skeletal muscles