[Digitonin-sensitive calcium pool and its change during synchronous division of Tetrahymena pyriformis cells].

A very significant intracellular pool of calcium, sensitive to digitonin action and different from one of free cytozolic Ca2+, has been shown to exist in the cells of ciliate protozoan T. pyriformis. Calcium content in digitonin-sensitive pool NdigCa2+ has been estimated throughout the cell cycle in synchronized culture of T. pyriformis. The value of NdigCa2+ decreased in the period of time prior to and at the cell division, whereas after the division itself it increased. The possible role of the calcium content changes of digitonin-sensitive pool in regulation of cytozolic Ca2+ level and in control of cell division is discussed.