Recent advances in radioimmunoassay technology for the juvenile hormones

Recent refinements in juvenile hormone radioimmunoassay technology now make this method significantly more sensitive and easier to use. Rabbit polyclonal antisera against (10R) JH III and racemic JH II have been developed to determine hemolymph hormone titers in the low picogram range. The antisera display minimal cross-reactivity with JH metabolites, JH analogs, and hemolymph lipids. One antiserum recognizes racemic JH I, II, and (10R) III almost equivalently, exhibiting 50% displacement between 100 and 130 pg per tube. Another antiserum is JH II-specific and exhibits 50% displacement at 35 pg per tube. Assay sensitivity has been enhanced by using (10R,11S) [methyl-3H]-JH II of very high specific activity (> 80 Ci/mmol) generated with Hyalophora cecropia accessory gland S-adenosylmethionine transferase and S-[methyl-3H]-adenosyl-L-methionine. Preparation of biological samples has been simplified with overall recoveries of JH from hemolymph ranging between 60 and 75%.