Endocrine Abstracts

Involutional changes of gonadal function in healthy ageing men are progressive and mostly of modest amplitude with considerable between- subject variability. Albeit some men may remain relatively spared, the occurrence of age-related changes are nevertheless well documented at the population level in both cross-sectional and longitudinal observational studies. These changes affect Sertoli cell function and spermatogenesis as well as Leydig cell function and testosterone (T) production and they are the consequence of both primary testicular changes and alterations in neuro- endocrine regulation of gonadotropin secretion. Men retain fertility until old age, but there are age-related reductions of testicular size, Sertoli cell mass and spermatogenic activity with moderate decline in semen volume, sperm motility and morphology with maintained sperm concentration. This is reflected in a progressive increase of FSH levels and marked decrease of the ratio of serum levels of inhibin over FSH. More than 20% healthy men over 60 yr present with serum T levels below the range for young men. This is the consequence of decreased Leydig cell mass and altered hypothalamic regulation of LH secretion. Together with a progressive age-related increase in serum SHBG levels, this results in a 50% reduction of the serum bioavailable fractions of serum T (i.e. free and non SHBG-bound T) between age 20 and 75 yr. Although the clinical changes of ageing in men are reminiscent of signs and symptoms of hypogonadism in young men, clinical relevancy of the decline in sex steroid levels in ageing men has not been unequivocally established and minimal androgen requirement for elderly men remain poorly defined and are likely to vary between individuals. Therefore, borderline androgen deficiency cannot be reliably diagnosed in the elderly and differentiation between “substitutive” and “pharmacological” androgen administration is not possible. Awaiting documentation of long-term risk-benefit ratio, a conservative approach to androgen treatment in elderly men seems appropriate.