MULTISIGNAL TRANSDUCTION OF THE PHEROMONOTROPIC RESPONSE BY PHEROMONEGLAND INCUBATIONS OF HELICOVERPA-ARMIGERA

The transduction of the pheromonotropic response by the pheromone glan ds of Helicoverpa armigera females was studied using an in vitro bioas say, Pheromonotropic activity was observed in the presence of the phor bol ester, phorbol-12-myristate 13-acetate, ionomycin and adenosine 3' -, 5'-cyclic monophosphathioate suggesting that several transducing sy stems (phosphatidylinositol breakdown; calcium levels; and adenylate c yclase activity) play a role in the mediation of the pheromonotropic a ctivation due to PBAN. The involvement and interaction of the differen t messengers was further studied using various inhibitors of protein k inases and calcium-calmodulin, The stimulation of pheromonotropic acti vity by PBAN was observed to be calcium dependent, however, at high PB AN concentration (20 pmol) there was a calcium-independent pheromonotr opic response, Experiments with the phorbol ester, phorhol-12-myristat e 13-acetate, indicated that the activation of pheromone production by protein kinase-C is calcium-dependent. Stimulation of the adenylate c yclase pathway by PBAN was also calcium-dependent. The interaction bet ween intracellular cAMP production and calcium levels was tested using a cAMP RIA, Studies concerning the elevation of intracellular cAMP le vels as a result of the ionophore, ionomycin, suggested that during th e pheromone gland stimulation, calcium activates adenylate cyclase.