ABSTRACT
INTRODUCTION In men, testosterone (T) is essential for the development and maintenance of various specific tissues with reproductive and nonreproductive tasks. In general, T exerts a widespread pattern of effects on metabolism, psyche, and body composition. This is most obviously seen in the difference between men and women. T-deficiency is associated with a magnitude of pathophysiological symptoms, clinically known as hypogonadism. Physicians define this condition by adverse traits in physical appearance, disturbed mental and cognitive traits, shifts in body composition, namely increased body fat content and reduced muscle mass. Physical abilities in androgen-deficient men are further attenuated by lower oxygen supply due to decreased hemoglobin concentrations and by poor glucose utilization. Also bone tissue is subject to strong regulation by T and its aromatization product, estradiol.
