A radioimmunoassay for 13, 14-dihydro-15-keto prostaglandin F2alpha with chromatography and internal recovery standard.

Antibodies to the 13, 14-dihydro-15-keto metabolite of prostaglandin F2alpha(PGF2alphaM) were raised in sheep using a bovine thyroglobulin conjugate of PGF2alphaM. Labeled 13, 14-dihydro-15-keto prostaglandin A2(PGA2M), 13, 14-dihydro-15-keto prostaglandin E2 (PGE2M) and PGF2alphaM were prepared from their corresponding high specific activity parent prostaglandins with swine kidney homogenate and purified using reverse phase liquid-liquid partition chromatography. A rapid method of column chromatography for use prior to radioimmunnoassay was developed. Mathematical corrections for the effect of recovery tracer on the logit/log transformation are presented with a new approach to expression of radioimmunoassay cross reactions allowing continuous expression of the variation of these cross reactions with displacement. These mathematical approaches are widely applicable to other radioimmunoassay systems and transformations. The assay was used for measurement in groups of human volunteers: males, females, women at delivery and paired venous umbilical cord bloods. A correlation between venous cord and maternal peripheral PGF2alphaM levels is demonstrated with a gradient from the cord plasma to maternal plasma.