AGING AND INSULIN-SECRETION

Aging in mammals has often been associated with decreased insulin secr etion and a subsequent deterioration in the ability to maintain glucos e homeostasis. However, recent studies have demonstrated that factors such as disease, obesity, and physical activity more closely reflect d iminished insulin secretion rather than aging per se. Thus, the purpos e of this article is to review recent studies of how biological aging, i.e. the process independent of disease states such as type II diabet es, may affect insulin secretion. To this end, this review will addres s the impact of aging on insulin secretion in terms of in vivo and in vitro assessment, as well as possible age-related alterations in the h ormonal and neural regulation of insulin secretion. Finally, this revi ew describes some evidence that alterations in the functional heteroge neity of the beta-cell population may represent a means by which the e ndocrine pancreas is able to maintain appropriate insulin secretion du ring senescence.