Endocrinology of the aging male.

Despite enormous medical progress during the past few decades, the last years of life are still accompanied by increasing ill health and disability. The ability to maintain active and independent living for as long as possible is a crucial factor for ageing healthily and with dignity. The most important and drastic gender differences in aging are related to the reproductive organs. In distinction to the course of reproductive ageing in women, with the rapid decline in sex hormones expressed by the cessation of menses, men experience a slow and continuous decline. This decline in endocrine function involves: a decrease of testosterone, dehydro epiandrosterone (DHEA), oestrogens, thyroid stimulating hormone (TSH), growth hormone (GH), IGF1, and melatonin. The decrease of sex hormones is concomitant with a temporary increase of luteinizing hormone (LH) and follicle-stimulating hormone (FSH). In addition sex hormone binding globulins (SHBG) increase with age resulting in further lowering the concentrations of free biologically active androgens. These hormonal changes are directly or indirectly associated with changes in body constitution, fat distribution (visceral obesity), muscle weakness, osteopenia, osteoporosis, urinary incontinence, loss of cognitive functioning, reduction in well being, depression, as well as sexual dysfunction. The laboratory and clinical findings of partial endocrine deficiencies in the aging male will be described and discussed in detail. With the prolongation of life expectancy both women and men today live 1/3 of their life with endocrine deficiencies. Interventions such as hormone replacement therapy may alleviate the debilitating conditions of secondary partial endocrine deficiencies by preventing the preventable and delaying the inevitable.