ABSTRACT
The steroidal agents are a group of compounds with remarkable diversity in target tissues and actions. Steroidal agents include androgens, estrogens, progestins, glucocorticoids, mineralocorticoids, cholesterol, bile acids, and cardiac glycosides. Receptors for steroids are found throughout the cardiovascular system of nearly every species examined. Not surprisingly, the cardiovascular system is the target of many steroid actions through either indirect effects or direct effects mediated by direct interaction of the steroids with vascular or cardiac cells. In addition, continued identification of non-genomic mechanisms of steroid action raise questions as to the diversity of cardiovascular tissues that may be susceptible to steroid-mediated effects. Similarly, increased awareness and identification of environmental or novel synthetic compounds acting through steroid receptors underscores the importance of understanding the cardiovascular effects of steroidal agents, especially with regard to toxicologic implications. Finally, the extensive hepatic metabolism of these agents coupled with the great diversity in target tissues leaves the steroids susceptible to a wide variety of drug, chemical, or physiologic interactions. This chapter is not intended to undermine the importance of steroid function in other classic target tissues; rather, the focus of this chapter will be on the known effects of steroidal agents on the vasculature and the heart, with special emphasis on identification of future areas for steroid research. Where possible, emphasis will be placed on human studies providing mechanistic information regarding the cardiovascular effects of steroidal agents.
