Altered cellular metabolism and intracellular and intercellular signaling with advancing age result in widespread changes in endocrine function. Several mechanisms interact in most systems to bring about the observed changes. Aging is associated with anatomic changes of the endocrine glands. In addition, with age, changes in hormone replacement secretion occur, including alterations in circadian or seasonal biorhythms, changes in pulsatile frequency or amplitude of growth hormone secretion, as well as absolute changes in mean serum hormonal levels. The three main hormone systems that show decline with age are the gonadal hormones (menopause and andropause), the adrenal steroids DHEA and DHEA-S (adrenopause), and the GH/IGF-1 axis (somatopause). (more…)

Pharmacodynamics describes the course of action of a drugs and aging at the effector organ level, in terms of duration and magnitude of action, and amplitude of and time to reach the peak action, for both therapeutic and adverse actions. Alterations in the number and affinity of drug receptors, postreceptor signaling processes, biochemical responses, homeostatic mechanisms, and body composition, in addition to higher likelihood of polypharmacy and concurrent pathological processes in older age, make elders more susceptible to adverse drug reactions, drug–drug interactions, or decreased/ increased sensitivity to some drug action. (more…)