Correlation between phosphatidylinositol degradation and cell division in embryonic chicken lens epithelia

Differentiation of embryonic chicken lens epithelial cells to form lens fibers is associated with a marked decrease in both the rate of phosphatidylinositol degradation and the rate of cell division. In cells of the central region of the lens epithelium, the rate of cell division also declines with developmental age. The present study measures phosphatidylinositol degradation in cultured explants of the central lens epithelium of chicken embryos of different ages to determine the extent of the correlation between phosphatidylinositol degradation and cell division in this tissue. The results show that the rate of phosphatidylinositol degradation also decreases during development and is proportional to the rate of cell division throughout the period from 6 to 19 days of development. Furthermore, stimulating cell division in central explants of lens epithelia of 19-day-old chicken embryos by culturing them in the presence of fetal calf serum produces a proportional increase in the rate of phosphatidylinositol degradation. These findings indicate that cell division and phosphatidylinositol degradation are tightly coupled in this tissue, and raise the possibility that phosphatidylinositol metabolism may regulate some aspect of the cell cycle.