The proposed research will examine neurohormone synthesis and secretion in insects using the hypertrehalosemic hormone (HTH) as the model. HTH belongs to the adipokinetic/red pigment- concentrating hormone family that is widespread among insects. These hormones all stimulate mobilization of fat body nutrient stores to elevate circulating metabolites for energy. HTH also stimulates heme synthesis during fat body mitochondrial maturation and acts synergistically with juvenile hormone to enhance protein synthesis. Hence, HTH is critical for regulating insect basal metabolism through effects on energy production/consumption. Measurements of HTH synthesis-secretion will be made by incubating corpora cardiaca with ?3H!tryptophan and determine the amount of ?3H!HTH formed using reversed-phase chromatography and scintillation spectrometry. The research will examine HTH synthesis-secretion relative to a series of physiological variables that include: age, sex, circadian rhythms, feeding, endocrine titers and effects by other parts of the nervous system. This research will provide a base of data for future investigations into how physiological effectors control neurohormone gene expression in higher animals. Physiological changes in response to environmental changes in animals are mediated by the nervous system and, in turn, by neurohormones, peptide hormones that are produced and secreted by the nervous system. This proposal describes studies on one such neurohormone, the hypertrehalosemic hormone (HTH) of the cockroach Blaberus discoidalis, a hormone involved in the mobilization of energy reserves from the fat body of the insect. The project will isolate the gene encoding HTH, and will study the physiological regulation of HTH synthesis at the gene level. The results should provide basic information about the role of neurohormones in controlling physiological responses to environmental stimuli. Such basic information may also be useful in future applications in the area of insect pest control.//
