Chapter 2 Genes, Hormones, and Aging

Abstract

This chapter discusses the problems of elucidating primary changes in cellular properties by considering the structural and functional changes in one endocrine tissue, the human adrenal cortex. This example amply illustrates that simple gathering of data on endocrine changes in aging, although valuable and necessary, does not shed light on molecular mechanisms. The chapter discusses the methods that can be used to address difficulties and the working hypothesis of many cell biologists in aging research that there are intrinsic stochastic cellular processes that may form the basis for primary age-related changes in endocrine and other tissues. However, although such permanent changes in cell properties, such as altered DNA methylation, certainly occur in aging, none of them has yet been shown to be responsible for age-related changes in tissue properties. It is suggested that an age-related intrinsic, irreversible change in cell phenotype could be triggered by long periods of exposure to hormonal or other factors (e.g., extracellular matrix proteins). The chapter also discusses the nature of the genes that are responsible for initiating these processes and for protecting against them.