Steroid Effects on Excitable Membranes

This chapter describes a number of steroid-induced effects at excitable cells that have been found to occur in vivo and relate these changes to changes that may occur in various processes involved in synaptic transmission and membrane excitability. It examines steroid interactions with lipid membranes and presents experimental results concerning the androgen modulation of ionic channels in androgen-sensitive muscles. Steroids act at a molecular level to modulate cell function. Early exposure of a cell during development to a wide variety of steroids and other substances can influence the molecular events that occur at the later stages of development. These are known as the organizational effects of the steroids. In the adult, the effects are activational rather than organizational, and the chapter defines some of the molecular events that underlie these activational effects. This chapter discusses the advantages and disadvantages of a cell culture approach in understanding steroid hormone action on excitable cells and the future directions that this field may take, particularly with regard to the application of the techniques of molecular biology for unraveling the changes that steroids may induce in excitable cells.