CELLULAR-LOCALIZATION OF ATRIAL-NATRIURETIC-PEPTIDE AND TISSUE KALLIKREIN IN THE HUMAN HYPOTHALAMUS

In the kidney, renal atrial natriuretic peptide (ANP) is considered to play an important role in water and salt homeostasis. Immunoreactive ANP in the brain of lower invertebrates, such as the rat, has been sho wn to be localized in the hypothalamus and septum. Several studies hav e investigated the possibility of a regulatory system in the brain sim ilar to that of the kidney. Since neuronal function is acutely sensiti ve to disturbances of the intracranial water and salt balance we have attempted to immunolocalize ANP-containing cells in the normal human h ypothalamus, using a polyclonal antiserum specific to ANP. Also, we ha ve observed tissue kallikrein (TK), using a polyclonal antiserum speci fic to TK, in the same areas as ANP. A regulatory role for TK on prola ctin has been suggested as the rationale for the co-localization of th ese two hormones in human prolactinomas. Therefore, it could be sugges ted that TK plays a similar role in the processing of precursor ANP in the brain. It is contemplated to examine the status of these peptides in patients with cerebral oedema.