Comparative study of the internalization and nuclear localization of amino acid type hormones in Tetrahymena and rat lymphocytes.

Tetrahymena pyriformis GL cells and rat thymic lymphocytes equally showed intranuclear incorporation of triiodothyronine, diiodotyrosine, histamine, serotonin, epinephrine and corticosterone--used as control--on exposure to labelled hormones. All hormones appeared in the nucleus in a predominantly heterochromatic localization. Lymphocytes, although smaller in size, incorporated more hormone than Tetrahymena. The intranuclear accumulation of corticosterone did not differ between Tetrahymena and thymocytes, and was high in both relative to total incorporation by the cell. Autoradiographically detected localizations did not notably vary with the type of cell or hormone.