Imprinting, digoxin uptake and storage in Tetrahymena.

Tetrahymenas after a single exposure to high concentration of digoxin, release glycoside into the culture medium even three days after removal of the drug. After nine or fifteen days, however, this effect subsides. Re-administration of digoxin causes the digoxin consumption (storage) of Tetrahymenas to increase. This observation indicates that the digoxin imprinting previously demonstrated in mammals occurs also in Tetrahymena. The experiments raise the possibility that also Tetrahymenas are capable of producing a digoxin-like substance detectable by radioimmunoassay.