Induction of lysosomal glycosidases by dibutyryl cAMP in neuroblastoma cells.

We have studied the regulation of lysosomal glycosidases during morphological differentiation of NB2a neuroblastoma cells. Cells treated with dibutyryl cAMP induced axon-like neuritis and showed a 2-4 fold increase in the activity of 6 lysosomal glycosidases, reaching their highest level after 5 days of treatment. Cells treated with retinoic acid, which induced dendrite-like neurites, did not show significant changes in the glycosidases activity although cell proliferation was also inhibited. There was no change in the pattern of the enzyme secretion during the dibutyryl cAMP treatment and morphological analysis using electron microscopy and cytochemical staining with acid phosphatase indicated the presence of lysosomes in the induced neurites.