[Determination of retinoids and retinol-binding protein]

The development of high-performance liquid chromatography (HPLC) in the late seventies, enabled us to measure various retinoids in the serum and tissue samples and has contributed to exciting new discoveries of retinoid field. Mainly, serum, retinoids has been measured by reversed phase HPLC with isocratic or gradient mobile eluent. In this paper, several HPLC methods for determining serum retinoids are reviewed. The discovery of plasma retinol-binding protein (RBP) in 1968 has shed new insight into retinoid metabolism. Due to the biochemical character of RBP, serum levels of this protein is a good marker for hepatic reserved function and urine levels for tubular proteinuria. Several methods for RBP determination are also reviewed.