Culture shock. Selective uptake and rapid release of a novel serum protein by endothelial cells in vitro.

摘要: A novel protein has been purified from fetal calf serum and serum-free bovine aortic endothelial cell conditioned culture medium. This consists of a single polypeptide chain reduced Mr 70,000 (70K protein) was separated albumin other proteins by ion-exchange chromatography immunoabsorption on Sepharose-coupled anti-70K antiserum. The 70K shown to be structurally immunologically distinct albumin, alpha-fetoprotein, vitronectin one- two-dimensional peptide mapping, amino acid analysis, enzyme-linked immunosorbent assay and/or immunoblotting. located in cytoplasmic granules irregular size distribution. Metabolic radiolabeling studies showed that the not biosynthetic product these cells; its location due selective uptake which cells were initially grown. After subconfluent cultures shifted medium, nearly 80% total measurable medium released between 0 20 min. Moreover, sparse, rapidly proliferating approximately 18-fold more within 2 min as compared dense, nonproliferating cultures. concentration estimated 400-600 micrograms/ml. Proliferating cells, 24 h after plating at an intermediate density, 250 pg protein/cell first exposure conditions. data provide evidence for is selectively internalized vitro turn under conditions such osmotic imbalance removal, or during periods cellular proliferation, we term "culture shock."