ENZYME-IMMUNOASSAY FOR 11-KETOTESTOSTERONE USING ACETYLCHOLINESTERASEAS LABEL - APPLICATION TO THE MEASUREMENT OF 11-KETOTESTOSTERONE IN PLASMA OF SIBERIAN STURGEON

A competitive enzyme immunoassay using 11-ketotestosterone (11-KT) cov alently coupled to acetylcholinesterase (AChE) from electric eel is de veloped. Ninety-six well microtiter plates are coated with pure mouse- anti-rabbit-IgG monoclonal antibody and competition is performed in on e-step reaction by adding successively 11-KT standard or samples, enzy matic tracer and 11-KT-specific antiserum. This assay is more sensitiv e (detection limit is 7 pg/ml) than radioimmunoassays previously descr ibed, and specificity was not modified by the use of enzymatic tracer. This assay can be performed in less than 5 hr. Validation of the EIA was achieved in a fish model, Siberian sturgeon (Acipenser baeri), by comparative determinations of 11-KT levels in plasma extracts using EI A and RIA. Application to the measurement of 11-KT in plasma of farmed Siberian sturgeon during the first reproductive cycle is reported.