FACTORS AFFECTING ALLATOSTATIN RELEASE IN A COCKROACH (DIPLOPTERA-PUNCTATA) - NERVE-SECTION, JUVENILE-HORMONE ANALOG AND OVARY

The effect of topical application of a juvenile hormone analog, 7S-hyd roprene, on juvenile hormone synthesis and the release into the hemoly mph of allatostatins (neuropeptides that inhibit juvenile hormone synt hesis) was assayed in adult male Diploptera punctata in which nerves t o the corpora allata were severed or left intact. Hormone production b y corpora allata was measured in vitro radiochemically; allatostatins were quantified by radioimmunoassay. Corpora allata with nerves intact were strongly inhibited by 7S-hydroprene; those with severed nerves ( denervated) were less inhibited. Hemolymph allatostatins were highly e levated (>3 nM) above normal (<0.04 nM) only in 7S-hydroprene treated animals with denervated corpora allata. This suggests that allatostati ns are normally released at nerve terminals within the corpora allata and that following denervation of the corpora allata allatostatins are released into the hemolymph and inhibit juvenile hormone synthesis le ss effectively. When ovarioles were implanted into 7S-hydroprene treat ed males with denervated corpora allata, hemolymph allatostatins were markedly reduced; juvenile hormone synthesis was higher after implanta tion of vitellogenic ovarioles than when a previtellogenic ovary was i mplanted. Thus, juvenile hormone analog acts on the brain to release a llatostatins and the ovary counteracts this action. These experiments indicate that both juvenile hormone and the ovary affect juvenile horm one synthesis through release of allatostatins.