title: Radioimmunoassay of plasma testosterone, with use of polyethylene glycol to separate antibody-bound and free hormone.
abstract: We have developed a reliable radioimmunoassay for testosterone in plasma, polyethylene glycol ("Carbowax 6000") being used to separate antibody-bound and free hormone. Testosteron is separated from interfering steroids, notably dihydrotestosterone, by liquid-liquid partition chromatography on infusorial earth (Celite). The assay is sensitive (9 pg for standards), precise, and accurate. The lowest measurable concentration fo testosterone is 350 ng/liter for plasma from men and 70 ng/liter for plasma from women. Intra- and inter-assay coefficients of variation were 6.9% and 9.7%, respectively, for plasma from men, and 9.6% and 11.8%, respectively, for plasma from women. Our method for separating antibody-bound and free hormone is practical and convenient and may be generally applicable to all radioimmunoassays of steroid hormones in plasma.
mesh_terms: D000906:Antibodies; D000937:Antigen-Antibody Reactions; D003429:Cross Reactions; D004967:Estrogens / Q000627:therapeutic use; D005069:Evaluation Studies as Topic; D005260:Female; D006801:Humans; D007202:Indicators and Reagents; D008297:Male; D011092:Polyethylene Glycols; D011485:Protein Binding; D011863:Radioimmunoassay / Q000379:methods; D012995:Solubility; D013256:Steroids / Q000097:blood; D013739:Testosterone / Q000097:blood* / Q000302:isolation & purification; D013997:Time Factors; D014316:Tritium
chemical_list: D000906:Antibodies; D004967:Estrogens; D007202:Indicators and Reagents; D013256:Steroids; D014316:Tritium; D011092:Polyethylene Glycols; D013739:Testosterone