Reversible Binding of ACTH to a Glass Surface

Abstract

The behavior of both natural ACTH and a synthetic adrenocorticotropic tricosapeptide has been studied in phosphate buffer at pH 7.4. At those concentrations which are normally used for bio-assay and which are also similar to the range of concentrations found in plasma, a very rapid apparent “inactivation” occurs. This was shown to be caused primarily by adsorption of the hormone to the surface of the glass rather than by oxidation. Furthermore, this adsorption onto the glass was found to be reversible, and the hormonal activity could be recovered by elution from the glass surface by a more acidic solution.