Does protein increase the production and function of testosterone?

A high intake of protein will increase levels of testosterone (free, unbound). High levels of protein lowers sex hormone binding globulin (SHBG) levels which will  cause  more free, unbound testosterone to become available for binding to the testosterone receptors (improving testosterone function). Remember, low intake of protein increases levels of SHBG which binds to testosterone causing it to be unavailable to its receptors (declining testosterone function).