DEVELOPMENT CHANGES IN JUVENILE-HORMONE AND JUVENILE-HORMONE ACID TITERS IN THE HEMOLYMPH AND IN-VITRO JUVENILE-HORMONE SYNTHESIS BY CORPORA ALLATA OF THE SILKWORM, BOMBYX-MORI

A simple method was developed to quantify hemolymph juvenile hormone ( JH) and JH acid in hemolymph extracts from Bombyx mori with an establi shed radioimmunoassay (RIA) for JH I, When various organic solvent ext racts of hemolymph were assayed by RIA, levels of non-specific binding of the labeled ligand in the assay were determined to be greater than 50% of the maximum amount of the label bound by the antiserum, When h emolymph was diluted with methanol:water:8.4 N ammonium hydroxide (10: 9:1) and extracted with isooctane, non-specific binding was only 50% h igher than control levels obtained with the assay buffer alone, The or ganic phase contained only JH and aqueous phase, JH acid. Consequently , this extraction method was used to prepare samples for RIA and enabl ed the separate measurement of JH and JH acid in hemolymph. With this method, changes in the hemolymph titers of JH and JH acid were determi ned from the third instar through early pupal stage of Bombyx mori. Ch anges in the in vitro secretory activity of corpora allata and brain-c orpora cardiaca-corpora allata complexes from fifth instar larvae were also determined by using JH I RIA of the incubation medium. (C) 1997 Elsevier Science Ltd.