RT Book, Section A1 Zaulyanov-Scanlan, Larissa A2 Baumann, Leslie A2 Saghari, Sogol A2 Weisberg, Edmund SR Print(0) ID 1172445751 T1 Hormones and Aging Skin T2 Cosmetic Dermatology: Principles and Practice, 2e YR 2009 FD 2009 PB The McGraw-Hill Companies, Inc. PP New York, NY SN 9780071490627 LK dermatology.mhmedical.com/content.aspx?aid=1172445751 RD 2024/03/29 AB It is well known that estrogen and testosterone play vital roles in the development of secondary sexual characteristics and are important for reproduction. There are also several ongoing investigations on the effects of these sex hormones in cardiovascular disease, neurodegenerative disease, mood, and cancer formation, as well as into their roles in adipogenesis and osteogenesis in women and men. With so many tissues expressing estrogen and androgen receptors, it is not surprising to find that several organ systems experience dramatic changes as sex hormone levels decline with advancing age. The first studies of sex hormone receptors in human skin and skin appendages began in the mid-1970s and examined estrogen receptors in breast cancer tissue,1 and testosterone receptors in human hair follicles.2 Since that time several studies have examined the roles of sex hormones in a variety of dermatologic and other disease states. While it has long been known that the skin has sex hormone receptors, the recent discovery of a second estrogen receptor (ER-β) has led to much interest in and new insights into the effects of sex hormones on various tissues including the skin. The aim of this chapter is to review the actions of sex hormones on the skin, specifically estrogen and testosterone, and to examine the roles of these hormones in skin aging.