Purification of adrenal chromaffin cells on Renografin gradients

Bovine adrenal medullary cells purified on discontinuous gradients of the radiopaque contrast agent Renografin contained about 20% more catecholamine than those prepared by centrifugation on Percoll gradients, a standard method for chromaffin cell purification. Catecholamine recoveries by the two methods were similar, suggesting increased purity in the Renografin preparation. Neutral red staining indicated that the cells prepared on Renografin gradients were approximately 90% chromaffin cells, compared to an average of 75% chromaffin cell purity obtained following centrifugation on self-generated gradients of Percoll. Cells purified on Renografin gradients were equivalent to Percoll-prepared cells by the criteria of maintenance in culture and secretory activity. Thus, density gradient centrifugation in Renografin is a rapid technique for producing adrenal medullary chromaffin cells of high purity and is superior to Percoll gradient centrifugation for this purpose.