Putrescine and spermidine changes in heat-synchronized Tetrahymena populations.

Putrescine and spermidine were the dominant polyamines in Tetrahymena cells. Spermine was present only in very small amounts. Changes in the amount of putrescine during and after the synchronizing heat treatment followed a definite quantitative pattern. Changes in the amount of spermidine were similar, though not so pronounced. The changes may be due to a varied influx of polyamines into the cells. Moreover, the exchange of polyamines between the cells and the culture medium must be specifically regulated since there seems to be a relatively greater accumulation of spermidine than of putrescine in the cells, and since spermine was almost excluded from the cells.