Radioreceptor assays analysis

KI Shestak, et al. Analysis of new opioid-like peptides by the radioreceptor assay. Ukr Biokhim Zh 62 23, 1990. 

ME Alburges, et al. Fentanyl receptor assay—Development of a radioreceptor assay for analysis of fentanyl and fentanyl analogs in urine. J Anal Toxicol 15 311, 1991. 

Llewellyn, L.E. et al., Measurement of paralytic shellfish toxins in moUuscan extracts comparison of the microtitre plate saxiphilin and sodium channel radioreceptor assays with mouse bioassay, HPLC analysis and a commercially available cell culture assay, EoodAddit Contam 18, 970, 2001. 

Soldner A, Spahn-Langguth H, Palm D, Mutschler E. A radioreceptor assay for the analysis of ATl-receptor antagonists. Correlation with complementary LC data reveals a potential contribution of active metabolites. J Pharm Biomed Anal 1998 17 111-124. 

One of the chief advantages of radioreceptor assays over most other analytical procedures is that, in many cases, very little or no extraction of the sample is necessary prior to analysis. Thus, to measure GABA in CSF, small portions of untreated spinal fluid are placed directly into the receptor binding assay tubes since other CSF substances do not appreciably... 

More elaborate extraction procedures are necessary in some situations. For example, to extract opioid peptides from brain for radioreceptor analysis, the tissue must first be homogenized in 0.1 N HCl (Simantov et al, 1977). Following centrifugation, the supernatant is lyophilized, resuspended in acid a second time, then centrifuged again to remove insoluble material. The supernatant is neutralized with 0.1 N KOH and the precipitate removed by centrifugation. The neutralized extract is lyophilized a final time and portions of this sample are analyzed by radioreceptor assay. 

In general, conventional extraction procedures can be used to prepare samples for analysis by radioreceptor assay. However, since some solvents may influence the binding assay, it is essential that preliminary tests be performed to rule out nonspecific interactions. In most cases, however, the sensitivity of the radioreceptor assay is such that the sample to be analyzed is sufficiently diluted to be rendered inactive in this regard. 

In order to demonstrate specificity, investigators have quantified samples using the radioreceptor assay and some other method of analysis, on the premise that if the values obtained are similar, then the radioreceptor assay is appropriate under the conditions employed. For example, the serum concentration of neuroleptics can be determined using a radioreceptor assay based on the dopamine receptor binding procedure (Creese and Snyder, 1977). To demonstrate the specificity of this assay, some samples were analyzed using both the radioreceptor assay and a radioimmunoassay (Table 3). The results obtained were virtually identical, indicating that the radioreceptor assay was measuring the same substance as that detected by radioimmunoassay. 

In the main this application deals with the analysis of plasma or semm for 25-OH-D3 and 1,25-(0H)2D3, two analytes which are present at low concentrations (25-OH-D3 1,25-(0H)2D3) in a relatively complex medium. It would appear at first sight that this presents a very difficult analytical challenge requiring the most extensive purification prior to quantitation. In the routine clinical laboratory, methods which are time-consuming and technically difficult are not as valuable as simpler and possibly, but not always, less specific methods. There is often a need in clinical situations for speed and simplicity and because of this, a considerable amount of development has taken place to produce simple and convenient assays in kit form, which depend upon the specificity of the saturation analysis quantitation procedure. The result is a method which couples solid-phase extraction with a radioreceptor assay which is both sensitive and specific. LC-MS meth-... 

Lovelace JL, Kusmierz JJ, Desiderio DM. Analysis of methionine enkephalin in human pituitary by multi-dimensional reversed-phase high-performance liquid chromatography, radioreceptor assay, radioimmunoassay, fast atom bombardment mass spectrometry, and mass spectrometry-mass spectrometry. J Chromatogr 1991 562 573-84. 

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