Effects of methylmercury on mitotic mouse glioma cells.

The effects of methylmercury on cultured mammalian cells were studied by light and electron microscopy. At 5 x 10(-6) M concentration methylmercury depressed the proliferation of mouse glioma cells almost completely and increased the mitotic indices. In the electron micrographs of the cells treated with 5 x 10(-6) M methylmercury for 4 hr, microtubules as mitotic spindle fiber were absent and chromosomes were scattered in a disorderly fashion in the cytoplasm. From these observations we concluded that exposure to methylmercury inhibits the cell mitosis by blocking the polymerization of tubulin to microtubules and results in the accumulation of the cells on the way of mitosis. Changes in behaviors of other mitotic apparatus and of fibrillar structures other than microtubules are also described.