1. Insulin shock produces modifications similar to those of adenohypophysectomy. The depletion of electron-dense granules from the axons is, however, restricted to the most anterior part of the R.M.E., and, in the C.M.E., the relative increase in the number of larger granules affects the 1,200–1,400 Å and the 1,600–1,900 Å size granules.