Change in insulin binding capacity of plasma membrane and nuclear envelope of Tetrahymena following a single long-term pretreatment and several short-term pretreatments (imprinting) with insulin.

Following insulin pretreatment (hormonal imprinting) of Tetrahymena cells there was an increased binding of insulin both in the plasma membrane and in the nuclear envelope of the offspring generations. A short (1 x 15 min) treatment did not produce imprinting in the plasma membrane but a 1 h treatment was sufficient. A similar short (1 x 15 min) treatment was enough to develop imprinting in the nuclear envelope and this is the treatment which induced the highest response. In the nuclear membrane there was a significant difference in the effect of 4 x 15 min and 1 x 60 min treatments but there was no effect in the plasma membrane. The effect of imprinting was observed after 48 h (16-20 generations). The repeated treatment of imprinted cells did not induce a further increase in the binding of the hormone.