DIFFERENCES IN THE COMPOSITION OF CHROMAFFIN GRANULES IN ADRENALINE AND NORADRENALINE CONTAINING CELLS OF BOVINE ADRENAL-MEDULLA

Several constituents of chromaffin granules were quantitatively determ ined in noradrenaline and adrenaline cells purified from bovine adrena l medulla. As far as secretory peptides are concerned noradrenaline gr anules contained slightly more secretogranin II, but much less chromog ranin A than adrenaline granules. This can be explained by the depende nce of the biosynthesis of chromogranin A on corticosteroids. Proteoly tic processing of chromogranin A and secretogranin II was higher in no radrenaline cells which was paralleled by a higher content of the proh ormone convertase PC2. Noradrenaline granules also contained a higher concentration of the vesicular monoamine transporter (vMAT2). No diffe rences were found for dopamine beta-hydroxylase, prohormone convertase PC1, carboxypeptidase I-I and synaptophysin. These results indicate t hat the secretory cocktail of peptides released from these cells diffe rs significantly between adrenaline and noradrenaline storing cells.