Hormone receptor changes during adulthood and senescence: significance for aging research.

Receptors for various hormones have been examined throughout the adult life span. In most of these studies receptor concentrations were found to decrease with increasing age, either during senescence or earlier in adulthood. In contrast, binding affinities did not change with age. Tissues and cells examined have included liver, brain, adipose tissue, skeletal muscle, prostate, fibroblasts, and lymphocytes. Receptors for steroids as well as membrane-active hormones such as insulin, glucagon, catecholamines, and prolactin were studied. Rats, mice, dogs, and humans have been employed. Changes in hormone receptor levels appear to constitute a common manifestation of the aging process, and offer interesting model systems in which to study the control of genetic expression during senescence.