Recent evidence, derived largely from studies on vertebrates, indicates that hormonal proteins and peptides occur as "families." Each family contains structurally related molecules, two or more of which may be found in a single species, or among diverse species in a phyletic group, or even among representatives of diverse animal phyla. Contemporary research attests to the importance of elucidating the structural basis of the consistancy and variability in peptide families as well as the functional and evolutionary relationships among such hormones. This project focuses on a newly discovered family of peptides isolated from crustacean and insect sources. Because of the simplicity in assessing its cellular actions, this invertebrate hormone family serves as an excellent model for evaluating peptide hormone control mechanisms, functional relationships, and hormone- receptor interactions. This project involves the isolation, characterization, and chemical synthesis of pigment-dispersing hormones (PDHs) from representative species of crabs, prawns, and crayfish. The purified and synthetic hormones will be tested for their relative potencies in diverse bioassay systems. By means of radioimmunoassays, the hormone levels in blood and neuroendocrine tissues will be monitored under various experimental conditions. Immunocytochemical tests will be employed to localize hormone-producing cells in representative crustaceans as well as in selected species of invertebrates. Depending on the progress in the above areas, studies will also be carried out to evaluate the molecular basis of hormone-receptor interactions. The knowledge derived from these studies would be of comparative interest to those working with neuropeptides from other invertebrates and vertebrates. The inferences drawn from the simple invertebrate system employed here would be of value in understanding the basis mechanisms of hormonal molecular diversity and actions. This project will provide opportunities for graduate and undergraduate students to participate in mainstream research in a rapidly advancing research field, thereby contributing to their career advancement in science and biotechnology.
