Specific insulin binding by, and imprintability of, the nuclear membrane of Tetrahymena

Cellular nuclei isolated from Tetrahymena were able to bind FITC-labelled insulin, and pretreatment with different concentrations of unlabelled insulin accounted for a decrease in FITC-insulin binding of the nuclear membrane. This strongly suggests an association of specific insulin receptors with the nuclear envelope of Tetrahymena. Nuclei isolated 1 week after primary exposure of Tetrahymena cells to insulin showed a 50% binding increase over the controls. This supports the implication that hormonal (insulin) imprinting also involves the receptors of the nuclear membrane of the imprinted cells.