SECRETOGRANIN-II IS SYNTHESIZED AND SECRETED IN ASTROCYTE CULTURES

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