A one and one-half day symposium will be held at the annual meeting of the American Society of Zoologists (New Orleans, December 27-28, 1987) to discuss the development, maturation and senescence of neuroendocrine systems in animals. Although the study of the senescence of neuroendocrine systems is in its early stages, research into this phenomena has accelerated at an amazing pace. The participants in this symposium include established senior investigators and younger scientists who have made significant contributions to their field of study. Their role will be to summarize and evaluate the progress that has been made in studies on aging in their area of expertise, to suggest new models for the study of development and senescence, and to chart new directions for future research.