Investigations on the radioimmunological determination of stilbenes in tissue samples from pigs

Based on the extraction procedures described for tissue of veal calves and following the introduction of reversed-phase-column chromatography as an alternative purification step, a radioimmuno-assay is described for the determination of DES in pork-tissue. When using the DES-specific antiserum AS 254 and depending on the tissue examined, the lower limits of detection were between 29-69 pg. A mean enor of 10.8% (CV between 13-17%) for the ecovery added to tissue samples and a CV between 3.6 and 10.5% for the reproducibility demonstrate a good reliability. Testing the 'stilbene-specific' antiserum AS 6139 by using 3H-DES as tracer revealed, the DES - and to a lesser extent also HEX - could be quantified with an acceptable degree of reliability when using the homologous RIA-system (use of DES and HEX resp. as calibration-standard), differently to DIEN; the possibility of a transformation of DIEN during the extraction into a compound exhibiting a higher cross reactivity is discussed. Application of the heterologous test system (quantification of the 'sample-stilbene' by using each of the other two stilbenes for calibration) yielded the expected over- and underestimations. Furtheron, in respect to total stilbenes, i.e. not knowing whether DES, HEX or DIEN are present in the sample, it has been shown, that the assay - though qualitative - is highly sensitive (59-86 pg lower level of detection) when DES is used as tracer and for calibration purposes. (orig.)