The long term goal is to understand the regulation of synthesis of juvenile hormone (JH), a major insect hormones involved in the control of reproduction. JH is synthesized by a pair of glands, the corpora allata (CA). The system studied is the reproductive cycle of the cockroach, Diploptera punctata, in which both the brain and the ovary interact to regulate the changes in JH synthesis required for egg development. This system serves as a model for investigating the regulation of hormone synthesis and should provide basic information which will be useful in development methods of controlling insect reproduction. The specific aims of the proposal are, first, to study biological parameters of D. punctata allatostatins, neuropeptide inhibitors of JH synthesis, that have recently been isolated, sequenced and synthesized. This will include the study of their localization and quantitation in the nervous system and hemolymph, their effects on CA of different physiological states, their binding to CA cells and effect on second messengers, and an investigation of the factors that elicit their release. A second goal is to isolate other allatostatins and allatotropins from the brain and ovary. Antibodies will be prepared to the synthetic allatostatins for immunocytochemical localization by light and electron microscopy and for quantitation of the allatostatins by enzyme-linked immunosorbent assay. JH synthesis, as determined by a direct short term in vitro radiochemical assay, will be used to measure the effect of allatostatins or extracts in which allatostatins and allatotropins are sought. Extracts will be purified by high-pressure liquid chromatography.