[Endocrine function in old age (70 years and over)].

Internists are frequently faced with the problem of interpreting hormonal values and the results of endocrine tests in elderly patients. In this review, endocrine changes observed in the course of the ageing process are systematically examined for each endocrine gland. The causes of the modifications observed can for the sake of simplicity be classified into three types: 1. Reduction of the hormone's metabolism with, subsequent to its prolonged half-life, a reduction of secretion due to an appropriate feedback mechanism, without modification of the secretory capacity of the glands involved (e.g. thyroid hormones and cortisol). 2. Reduction of hormonal secretion as a consequence of loss of glandular mass (e.g. the gonads). 3. Changes in the sensitivity of target cells to a hormone (e.g. insulin, ADH, catecholamines, lactotrope cells, TRH and hypothalamus to steroids) due to either loss of receptors or modifications in post-receptor events.