Ouabain binding of the rat's heart muscle cells after neonatal glucocorticoid (triamcinolone) treatment.

In adult rats the ouabain-sensitive ATP-ase activity of the heart muscle as well as the amount of specifically bound 3H-ouabain decreased by 1/3 as a result of a single triamcinolone treatment undertaken in the neonatal period. Neonatal ouabain treatment did not alter the triamcinolone binding of the thymus of adult animals. The experiments again call attention to the phenomenon that the steroid hormones, even though specific for their target cells, are able to induce "alien" imprinting when administered in the neonatal period. They are also able to bind to steroid receptors of other cells altering, thereby, the responsiveness of these cells in adulthood.