innately determined cortical organization undergoes further physiological maturation. To understand the anatomical basis of these changes during development and specifically to explore the dynamics of maturational plasticity, we will examine structural reorganization in developing visual cortical neurons following retinal blockade. In summary, our approach is to combine histochemical, immunohistochemical, ultrastructural, and physiological observations to yield an integrated understanding of metabolic adjustments to altered functional demands within developing and mature neurons of the primary visual cortex.

The long-range goals of this project are: (1) to evaluate the effects of prenatal exposure to environmental chemicals on the subsequent reproductive capacity of the offspring; (2) to investigate the mechanisms involved in the production of subfertility in mammals as a result of their in utero exposure to foreign chemicals; (3) to assess the transplacental carcinogenic potential of these compounds; (4) to study the physiologic disposition and metabolism of these compounds in the pregnant animal and fetus; (5) to study chemico-biological interactions of transplacental toxicants, with special emphasis on structure-activity relationships; (6) to determine if prenatal exposure to environmental agents can alter the cytoplasmic receptors for steroid hormones in reproductive tract tissues; (7) to develop and utilize organ culture systems to study the effects of environmental chemicals on the fetal ovary and reproductive tract in vitro; and (8) to evaluate the above animal models as predictors of human response. Special attention is given to diethylstilbestrol (DES).

Intercellular RNA transport is a potentially important means of cell-cell communication. In the nematode C. elegans the RNA channel SID-1 is essential for the cell-to-cell transport of silencing RNAs, SidTI and SidT2 (SidT1/2) are the highly conserved vertebrate homologs and published reports indicate that fish, mouse, and human versions of SidT1/2 have