Tags: Protein.
Transthyretin (TTR) is a serum and cerebrospinal fluid carrier of the thyroid hormone thyroxine (T4) and retinol-binding protein bound to retinol. This is how transthyretin gained its name transports thyroxine and retinol. The liver secretes transthyretin into the blood and the choroid plexus secretes TTR into the cerebrospinal fluid.TTR was originally called prealbumin (or thyroxine-binding prealbumin) because it ran faster than albumin on electrophoresis gels.