The role of receptors of the plasma membrane and nuclear envelope in the failure of insulin imprinting in starving Tetrahymena.

Starvation for 2 h does not disturb the insulin binding of Tetrahymena. At the same time imprinting does not develop at the first encounter with insulin and a down regulation is observed after 168 h. Starvation for 2 h reduces the insulin binding of the nucleus to the half value after starvation for 24 h and this change in binding becomes settled by 48 h. Imprinting is not elicited either in the nuclear membrane. The down-regulation can be observed also after 48 h but it is not present in the 168-h measurements. The experiments emphasize the increased sensitivity of binding sites of the nuclear envelope and the role of it in the development of imprinting.