Rapid induction of anaphase in competent cells by hypotonic treatment.

After brief exposure to hypotonic solutions cultures of human lymphocytes and PtK2 cells revealed a significant increase in the frequency of anaphase cells. Hypotonic solutions of potassium chloride, sodium chloride, sodium citrate and dilute culture medium all induced a flux of anaphase A after 30 sec treatment. PtK2 cells were able to proceed through to anaphase B and telophase after hypotonic treatment but human lymphocytes were arrested in anaphase A unless ATP was added to the hypotonic solution. In the experimental regime which was used, neither treatment with nocodazole nor the calcium ionophore A23187 was able to mimic the response to the hypotonics, and it is suggested that the primary induction of anaphase may involve a change in the kinetochore. Brief hypotonic treatment of actively growing cultures provides a simple method of increasing the frequency of anaphase cells for use in various investigations.