ASSAY OF PROTEIN HORMONES RELATED TO HUMAN REPRODUCTION: PROBLEMS OF SPECIFICITY OF ASSAY METHODS AND REFERENCE STANDARDS

Abstract

1 ABSTRACT 1.1 Assays of protein hormones have wide and numerous applications in human reproduction research and clinical practice. Both bioassays and immunoassays of these hormones depend upon comparison with suitable reference standards. Because they are so much cheaper, easier to replicate, and more sensitive, immunoassays are rapidly replacing bioassays for these human hormones in research and in clinical practice. Immunoassays, however, vary widely in their degree of specificity for different molecular forms, and the specificity of assay systems for each hormone should be rigorously assessed. The problem is especially complex with the glycoprotein hormones because of their close structural similarity: current research reveals that the α subunits, comprising about half the molecule of pituitary TSH, FSH, and LH, are very similar in all these hormones. It is likely that this is one of the major causes of non-specificity in current systems of immunoassay for these hormones. 1.2 A number of recommendations are made: on specificity criteria, on the provision of reference standards and immunoassay reagents, and on the need for agreement on quality control of these reagents.