Quantitative analysis of steroid hormone receptors and their messenger ribonucleic acids.

Ligand binding will remain the basic technique for receptor determinations in many laboratories. It can easily be set up and it is inexpensive. It has, however, the disadvantage of requiring relatively large amounts of tissue or cultured cells, if the proper multipoint measurements for Scatchard plots are to be done. Furthermore, each of the bound/free separation techniques mentioned above has its own caveat that has to be respected if analytically correct results are to be obtained. The great advantage of receptor immunoassays is their technical simplicity and the possibility of measuring a single dose of a receptor sample (in contrast to the Scatchard plot approach in ligand-binding assays). The possibility of using a single dose (even if assayed in duplicate) is a very valuable feature in all instances when only small tissue samples are available for assay. It would be very attractive for many laboratories to set up their own receptor immunoassays. The availability of suitable antibodies may not be a major obstacle. However, the necessity of possessing a supply of a highly purified receptor standard preparation may pose a problem. This is why commercial kits seem to be used so frequently. The analysis of receptor mRNA is a complement of or alternative to receptor quantitation. It must be realized, however, that special skills, as well as a molecular biology laboratory environment and equipment, are required for successful analytic work in this area. Solution hybridization is to be preferred as an approach to obtain results of a quantitative character. However, the specificity of hybridization should be checked by Northern blots. The same is true for dot/slot hybridization, which is a suitable method for semiquantitative assessments of a series of samples. Last but not least, the in situ hybridization provides invaluable information on the tissue and cell distribution of the mRNA analyzed.