[Senile hypogonadism in man and hormone replacement therapy]

Aging is accompanied by a progressive decline of testicular function. Whereas fertility persists until a very old age, endocrine function declines progressively and at age 70 yrs, more than 25% of men have hypogonadal testosterone levels. This decline in testosterone plays an important role in a series of signs and symptoms that accompany the aging process such as a decline in virility, in libido and sexual activity, muscle mass and strength, decline in bone mass (osteoporosis), an increase in abdominal fat mass and a decrease in the feeling of general well being. Most of these signs and symptoms have a multifactorial origin, nevertheless, androgen substitution generally improves most of these symptoms, increasing muscle mass and strength, improving libido and sexual activity, decreasing abdominal fat and improving insulin sensitivity as well as the sense of well being, effects which suggest a role of androgen deficiency in their genesis. Side effects of this substitutive therapy, mainly at the level of the prostate, with possible stimulation of a prostatic carcinoma, should be carefully looked for. Before starting any androgen therapy, the presence of a prostatic carcinoma should be excluded by rectal examination and PSA measurement, eventually, in case of doubt, complemented by transrectal echography. Presence of a prostatic carcinoma is an absolute contraindication for androgen therapy. During treatment, development of side effects should be traced by a six monthly rectal examination and PSA determination as well by monitoring of hematocrit and lipid profile.