Sex steroid signaling in the airway

The influence of sex hormones (estrogen, progesterone, testosterone) in the biology and pathophysiology of various organ systems is being increasingly recognized. While sex steroid effects, especially estrogens, on the cardiovascular system have been well studied, clinical and emerging bench research evidence exists for the role of sex hormones in airway and lung physiology and in diseases such as asthma, chronic obstructive pulmonary disease, and pulmonary fibrosis. In this chapter, we briefly define what sex differences exist in airway or lung structure and function under normal conditions, the potential role of sex steroids at different time points in life and in specific disease states, setting the stage to explore whether and how sex hormone signaling mechanisms may be contributory. We focus on the mechanisms by which estrogens, progresterone, and testosterone influence airway smooth muscle and epithelium in regulating airway tone and the potential contribution of these hormones in airway remodeling.