ABSTRACT
The well-established regulatory action of hormones on metabolism has been briefly reviewed in the preceding four chapters (Chapters 9-12). The many changes of this regulation with aging are well established; however, the onset, extent, and pathologic consequences of these changes vary with each individual endocrine gland considered. As already mentioned for the endocrine glands previously considered, there is significant individual heterogeneity in the ability of the elderly to maintain metabolic balance in response to internal and external challenges disruptive of homeostasis. One illustrative example of these aging-associated changes is the altered regulation of carbohydrate metabolism by the pancreatic hormones, insulin and glucagon. Carbohydrates, such as sugar and starch, are derived from aldehyde and ketone compounds. They represent, with proteins and lipids, the major energy-containing components involved in human nutrition (Chapter 23).
