Colocalization of corticotropin- releasing factor and vasopressin in the paraventricular nucleus of the human hypothalamus

The anatomical relationship between corticotropin-releasing factor (CRF)- containing cells and arginine vasopressin (AVP)-containing cells in the human hypothalamus was investigated by immunocytochemistry. In the paraventricular nucleus of the hypothalamus (PVH), CRF-like immunoreactivity (CRF-LI) was present exclusively in parvocellular cells, while AVP-like immunoreactivity (AVP-LI) was present in both parvocellular and magnocellular cells. No CRF-immunoreactive neurons were observed in the supraoptic nucleus. All CRF-immunoreactive parvocellular cells in the PVH were also AVP immunoreactive. We confirmed the presence of AVP in the CRF-immunoreactive cells by using two kinds of anti-AVP antisera, one of which recognized the side chain of AVP while the other recognized the ring structure of AVP. Colocalization of CRF-LI and AVP-LI was observed not only in the same perikarya but also in the same nerve fibers of parvocellular cells. The present results raise the possibility that AVP and CRF may be secreted together into the human portal circulation.