Support is requested by the Animal Models Research Center, Department of Biology, Boston University, for a Training Program (four pre doctoral trainees) in reproductive endocrinology. The faculty represents a wide range of experimental expertise and animal model use, both vertebrate and invertebrate. The merit of a comparative approach for the identification of suitable animal models for investigation of particular questions or problems has been recognized by the National Academy of Science. Using this approach, by the selection of a suitable model, particular problems relative to human health issues can be advantageously investigated. In addition, a comparative approach uncovers new models by expanding our understanding of particular adaptations of animal species and increases the available models for research. Finally, with the decline in species diversity and populations, additional information related to reproduction of a wide range of animal species is warranted. Specific areas of research include behavioral endocrinology, and the neuroendocrinology of reproduction; the regulation of neural aromatase, the role of estrogen in the regulation of neural development and spermatogenesis; the regulation of c-mos transcription in mammalian germ and somatic cells and the regulation of apoptosis; transcriptional control mechanisms for estrogen receptors, cell growth and cell cycle studies; transcription factors and oncogenes; the role of caspases and ecdysone in oogenesis; estrogen; progesterone in the regulation of vertebrate vitellogenesis and the impact of xenobiotics; the role of sex differentiated patterns of growth hormone secretion in the regulation of heptic p450 gene expression; xenobiotics and peroxisome proliferators; fetal and neonatal adrenal maturation and the role of leptin during pregnancy. Training will include formal classroom instruction, upper level seminars and laboratory research rotations using behavioral, physiological, genetic, cellular, and molecular and biochemical approaches. Field research will play an important role in linking the natural reproductive biology of certain species to the environment and to laboratory studies. Trainees will be accepted into the Ph.D. program in Biology at Boston University, which has a large cohort of graduate students. The broad range of disciplinary and experimental expertise represented by the general faculty, the quality of the physical facilities, and the demonstrated commitment of the University to biological sciences in general and to this project in particular ensures a superb training environment. In addition, the available interdisciplinary programs in neuroscience and bioinformatics provide support in reproduction-related neurobiology and the developing fields of genomics and proteomics.