Sex hormone-binding globulin (SHBG) is thought to mainly function as a transporter and reservoir for the estradiol and testosterone sex hormones. However it has also been demonstrated that SHBG can bind to a cell surface receptor (SHBG-R). The SHBG-R has not been completely characterized. A subset of steroids are able to bind to the SHBG/SHBG-R complex resulting in an activation of adenylyl cyclase and synthesis of the cAMP second messenger.  Hence the SHBG/SHBG-R complex appears to act as a transmembrane steroid receptor that is capable of transmitting signals to the interior of cells.
January 9, 2009 – Early in the morning, I go to Emory Johns Creek Hospital to get the CT scan. It is uneventful, as radiology appointments typically are, and I go home. We are having a houseful of people that night for a neighborhood party and there is a lot to do. Two hours later, a nurse calls from Dr. Gupta’s office and says he would like me to come in as soon as possible so he can discuss the CT results with me. I am annoyed by this, but still mindful that if a doctor wants to talk “right away,” then I should probably go.