Permeability of a nuclear membrane: changes during normal development and changes induced by growth hormone.

The ion permeability of the nuclear membrane envelope of salivary gland cells (of the midge Chironomus thummi) undergoes changes during development. Following the early fourth instar stage, permeability falls to about one-fifth of its base value over a period of 3 to 5 days of development of the animal, and then rises again over the next 2 to 4 days. The falling phase of the change can be reproduced within 1 hour by injections of the growth hormone ecdyson.