Proteins from a large variety of sources have been sequenced in the facility. These include Herpes simplex virus I DNA replication protein (Fierer and Challberg,LVD), human monocyte proteins (Kan, LCI), neutrophil NCF-3 cytosolic factor (Kwong and Leto, LCI), Plasmodium sexual stage proteins (Williamson and Kaslow, LPD), alpha glucosidase from Candida (Williamson, LCI), Vaccinia ECO 105 (Ahn, LVD), TGFbeta3 (A. Roberts, NCI), and Duffy blood group antigen (Miller, LPD). High performance liquid chromatography (HPLC) was utilized to demonstrate the production of endothelins by novel cell types. Primary rat astrocytes were shown to produce and release endothelin-3 as well as to possess receptors for endothelin -1, -22, and -3. These results indicated that astrocytes serve as a potential extravascular source of intracerebral regulation. The secretion of endothelin -1 and -3 by astrocytes was shown to be independently regulated. Further studies demonstrated that human macrophages synthesize and secrete endothelins -1 and -3 indicating that macrophage-derived endothelins may have an essential function in blood vessel physiology, and that aberrant production may contribute to vessel pathology.
