Alpha-melanocyte stimulating hormone promotes neurite outgrowth in chromaffin cells.

Chromaffin cells from adult bovine adrenal medulla were found to develop neurites when cocultured with pituitary intermediate lobe (IL) cells. In coculture 51.7% of the chromaffin cells extended neurites compared with 12% in control cultures (chromaffin cells alone). A soluble factor released by IL cells was apparently involved as medium conditioned by contact with IL cells also promoted neurite outgrowth. Moreover, the addition of alpha MSH, one of the pro-opiomelanocortin-derived peptides secreted by IL cells, alone reproduced this effect in a dose-dependent manner. The data provide evidence for a neurotrophic role of alpha MSH.