Binding and internalization of 3H-epinephrine in Tetrahymena

Exposure of Tetrahymena to exogenous epinephrine is followed by appearance of the hormone in the cell membrane, intracytoplasmic vacuoles and nucleus. The intra-nuclear localization is always heterochromatic. Only a minor proportion of the applied epinephrine dose gains access to the nucleus, while the bulk of it attaches to the membrane.