The stable currents which have been demonstrated to enter the ventral and leave the dorsal surface of the vitellogenic oocyte of Blattella germanica are a very early and a very striking demonstration of dorsal ventral polarity. They may represent the earliest physiological process to be directly correlated with the establishment of a dorsal ventral polarity. To elucidate the ionic basis of these currents Dr. Kunkel plans to use ionic replacement, channel blocking and metabolic poisons to affect the pattern of measurable currents. The effects of natural serum components present during vitellogenesis on the currents will also be examined, including vitellogenin, other serum proteins and juvenile hormone. The effects of removal of the follicle epithelium on the currents will be determined. The physiology of these currents will be investigated using the vibrating probe and patch clamping. This study will allow Dr. Kunkel to examine the origin and physiological basis of dorsal ventral polarity. %%% The establishment of asymmetry is an early and fundamental step in the development of an organism. It occurs before fertilization. The unfertilized egg already shows polarity. Dr. Kunkel is investigating the establishment of this polarity early in the development of the egg.