Radioimmunoassay of steroid hormones

A list is given of steroids currently determined using the RIA method based on the reversible interaction of labelled and non-labelled steroids within the binding points of specific antibodies. Steroids do not have the properties of antigens, and antibodies are therefore obtained from conjugates of steroid derivatives with macromolecules where the steroid has the function of hapten. The most important synthetic methods of preparing the given derivatives are listed, and questions of the relation of the specificity of the antiserum and the structure of the respective derivative are discussed, the basic data characterizing the antiserum (titre, affinity and specificity) are described and methods are given used for measuring these variables. The technical aspects of RIA and the differences between the RIA determination of steroids and of other substances are given. The Amersham Radiochemical Centre antigens, kits and steroid hormones are recommended for use. (L.O.)