This 5-year renewal includes requests for support for the Center's AIDS- related research programs and improvement and Modernization projects. The application reflects the new directions of the Center to enhance its scientific capabilities, with primary emphasis on expanding the use of nonhuman primates as models of human disease. New opportunities at the Center will focus on development of outstanding research programs, consistent with the goals of using nonhuman primates. The aims of this application are to: 1) provide support requisite for excellence in the scientific programs which use the Center's unique nonhuman primate (NHP) resources for solutions of human and animal health problems; 2) enhance the Center's role as a regional, national and international resource by upgrading laboratories, animal housing facilities and equipment and by increasing interinstitutional collaborations; 3) pursue practices that will assure the continued availability of quality NHPs for local and national biomedical research through support of unique programs, i.e., the Assisted Reproductive Technology (ART) Laboratory and the Specific Pathogen Free Colony; and 4) maintain practices that favor the highest standards of humane and responsible animal care. These aims are designed to facilitate the research programs housed in three divisions. These programs, which focus on areas identified as high priority by NIH, are summarized below. The Division of Infectious Diseases is involved in research that includes molecular basis for simian immunodeficiency neurotropism, trans-dominant gene therapy as an approach to treat primate lentivirus infections, effects of altered cell tropism on the pathologic potential of type D retrovirus, the role of T and B cell responses in the control of retrovirus infections, and immunologic basis of fetal tolerance. The Division of Neuroscience is involved in projects that include the molecular and cell biology of Parkinson's disease, drug addiction and depression, growth receptor genes involved in tumorigenesis, molecular control of sexual differentiation, dietary components essential for brain development, molecular responses of the brain to injury and gene therapy of the nervous system. The Division of Reproductive Sciences is involved in projects that include in vitro fertilization and embryo transfer, causes of premature labor, neuroendocrine regulation of the menstrual cycle, regulation of prolactin secretion and postpartum depression, role of sex steroids in ovarian function and vascular occlusive disease, hormonal control of the reproductive tract and gene expression in testis and sperm. Support services for the intra- and extramural research programs are provided by the Divisions of Research Services, Primate Medicine, and Facilities and Properties. Research Services perform specialty procedures with wide application to research groups. Primate Medicine is responsible for animal procurement, breeding, feeding, housing and health. Personnel in Facilities and Properties aid in development and maintenance of the physical resources.