Localization of neurophysin within organelles associated with protein synthesis and packaging in the hypothalamoneurohypophysial system: an immunocytochemical study.

Electron microscopic immunocytochemical localization of neurophysin in the hypothalamo-neurohypophysial system of mice has been studied by using the pre-embedding staining approach to the unlabeled antibody-enzyme technique of Sternberger. In supraoptic cell bodies, peroxidase-antiperoxidase reaction product was localized within cisternae of the nuclear envelope, rough endoplasmic reticulum, and Golgi saccules but not in GERL (Golgi-associated smooth endoplasmic reticulum from which lysosomes arise). Reaction product was also present in secondary lysosomes. Secretory granules in supraoptic perikarya and posterior pituitary Herring bodies were likewise immunoreactive. These findings with the unlabeled antibody-enzyme technique provide conclusive evidence for the localization of an antigen within cellular organelles associated with protein synthesis and packaging.