Secretogranin II is synthesized and secreted in astrocyte cultures

Astrocyte cultures from rat brain were analyzed for their ability to synthesize and secrete secretogranin II (chromogranin C). Northern blot analysis of polyA-selected RNA established the presence of secretogranin II mRNA in these cells. By radioimmunoassay, 11.6 fmol/10(6) astrocytes of secretogranin II was found in these cells. About twice the amount was released into the medium within 3 days. Secretogranin II within the astrocytes was practically unprocessed, as shown by HPLC. These results establish for the first time that astrocytes in vitro synthesize and secrete a protein of the acidic chromogranin family.