The objective of this research is to develop an in vivo system for study of the effects of maternal serum Insulin.like Growth Factor (IGF) levels on fetal rat development. The recognition that growth factors may influence several aspects of development has excited interest in defining the true range of their effects and action mechanisms. IGF.II has been implicated as a regulator of embryogenis and fetal growth, and the proposed research seeks ultimately to determine the soundness of this implication. The experimental approach will utilize IGF.II secreting tumors to raise maternal IGF.II levels, and explore the relation of these elevated levels to placental.binding and passage of the factor, and to patterns of fetal growth. The initial objective is to determine the effectiveness of the tumor system for perturbing placental and fetal IGF.II levels. Subsequent efforts will be devoted to reducing the interpretive complexity of the system to a level that will permit direct analysis of IGF.II effects on the fetus. If successful, this system may generate data not easily available by other approaches, and increase our understanding of regulatory mechanisms of growth and development. //
