Measurement by radioimmunoassay of prostaglandins as their methyl oximes

Abstract

Antisera have been raised to the following prostaglandins as their methyl oximes; PGE2, PGD2, 13-14-dihydro-15-oxo PGE2, 13,14-dihydro-15-oxo PGF2 alpha, 6-oxo PGF1 alpha, 6-oxo PGE1 and thromboxane B2. These antisera have good specificity and sensitivity and their use allows the immediate treatment of biological fluids with oximating solution which prevents sample decomposition during storage. A methyl oximating reagent is described which gives greater than 95% conversion of PGs to their methyl oximes by treating samples at 20 degrees C overnight. The use of this reagent allows easy and reliable sample derivatisation prior to assay with the above antisera. Since the antisera (with the exception of that for thromboxane B2) do not recognise the underivatised PG or the oxime (=NOH) form, oxime formation can be carried out in parallel with methyl oxime formation and the oximated portion of the sample can act as a "reference" for the methyl oximated portion, which will allow non specific interference to be recognised.