Electron microscope immunohistochemical localization of neurophysin in the rat with hereditary diabetes insipidus.

In order to study the subcellular distribution of neurophysin in the rat with hypothalamic hereditary diabetes insipidus (DI), an immunoelectron microscopic localization of neurophysin was performed in the hypothalamo-neurohypophysial system of both homozygous and heterozygous DI rats. Whereas in control rats neurophysin was localized in the granules present in the secretory neurons, in the homozygous DI rats neurophysin was found in the granules and outside the granules in the perikarya and axons of neurons of both supraoptic and paraventricular nuclei. In the heterozygous DI rats findings similar to those observed in homozygous DI rats were observed, although in the posterior pituitary, the exgranular material appeared to be less abundant than in homozygous DI rats. These results clearly demonstrated that in hyperstimulated neurons neurophysin was distributed in both granular and extragranular compartments.