Hormone uptake and morphological changes in cultured pituicytes exposed tooxytocin and vasopressin

Enzymatically dispersed cells, isolated from adult female rat neural lobes, were cultured for 7 days. Routine cultures showed pituicytes with compact, sometimes ovoid, cell bodies. The cytoplasmic processes of these cells exh ibited several varicosities and made contact with neighboring cells forming networks. The cultured pituicytes were immunocytochemically characterized using antisera to glial fibrillary acidic protein and to S-100. Most pituic ytes, when exposed during culture to oxytocin (OXY) and vasopressin (VP; 1 mu M each), were devoid of their characteristic processes. Immunocytochemic al staining for OXY or VP revealed that the pituicytes were capable of inco rporating these hormones during culture. In cultures without added hormones , no significant staining reaction for OXY or VP could be detected. The lac k of projections in pituicytes exposed to the hormones during culture is in agreement with the morphological changes observed by other authors in situ after acute hormone release. The uptake of OXY and VP may be indicative fo r a regulatory mechanism, by which the pituicytes control the amount of hor mones present in the intercellular space.