A rapid assay for binding estradiol to uterine receptor(s)

✍ Scribed by T. Erdos; M. Best-Belpomme; R. Bessada

• Publisher: Elsevier Science
• Year: 1970
• Tongue: English
• Weight: 474 KB
• Volume: 37
• Category: Article
• ISSN: 0003-2697
• DOI: 10.1016/0003-2697(70)90044-8

✦ Synopsis

Uterine cytosol contains two types of estradiol (E) binding sites.l Binding to type A sites occurs at low E concentration, the affinity is very high, the number of the binding sites is limited, .and the complex formed is slowly reversible. Binding to ,type B sites occurs at higher E concentrations, the affinity is low, the number of binding sites is very high, and the complex formed is rapidly reversible (l-3). Three methods are available to measure the concentration of E bound to type A sites: Sephadex filtration (2-8), extensive dialysis (2), and the charcoal method (9-12). All have some drawbacks: the first is relatively laborious, the second is too slow, and graphic correction is needed to interpret the values obtained by the charcoal method.

We have devised a method that involves adsorption of a uterine extract, labeled with tritiated estradiol (EH3), on small hydroxyapatite (HAP) columns at O"C, rapid elution of unbound E with buffer, followed by quantitative transfer of the HAP into counting vials for direct measurement of the retained radioactivity.