Electron microscopic lesions of supraoptic and para-ventricular nuclei of rat thalamus in adrenal insufficiency.

Ultrastructural changes in the supraoptic and paraventricular nucleus of the rat brain in adrenal hypofunction evoked by bilateral adrenalectomy are described. Marked ultrastructural changes were observed in the ultrastructure of the neurons of the paraventricular nucleus, the changes being less pronounced in the suproaoptic one. The changes indicated enhanced synthesis of neurosecretory granules activating the so-called "creation" surface of the Golgi complex. The increased synthesis of neurosecretory granules in adrenal hypofunction might indicate that some of them could be CRF carriers. It is not possible, however, to find by exclusively morphological methods the morphological equivalent of CRF. The higher intensity of the changes found in the paraventricular nucleus suggests that the latter possibly plays a more important role in the regulation of ACTH secretion.