Enkephalin-like immunoreactivity in human adrenal medullary cultures

Normal adult human chromaffin cells in culture contain abundant immunoreactive enkephalin and exhibit spontaneous and nerve growth factor-induced outgrowth of processes. In cultures of adrenals from two age-matched white males, approximately 70 per cent of chromaffin cells from one case and 50 per cent from the other contained immunocytochemically demonstrable leuenkephalin-like material. There was no apparent correlation between enkephalin-like immunoreactivity and capacity for process outgrowth. Cells with and without processes stained for enkephalin, and the percentages of stained cells with processes appeared to change in proportion of overall process outgrowth. Numerous cells with and without processes also failed to stain for enkephalin. Marked variations in sizes of stained cells and in distribution and intensity of staining were observed in all of the cultures. These findings suggest that adult chromaffin cells are heterogeneous at a number of levels.