Immunocytochemical localization of amidating enzymes in the sustentacular cells of phaeochromocytoma

ABSTRACT

To evaluate the presence of amidating enzymes in phaeochromocytoma. Materials and An immunocytochemical study of 21 cases of benign and malignant phaeochromocytomas of the adrenal medulla, was carried out to demonstrate peptidylglycine-alpha- amidating monooxogenase enzymes, using avidin-biotin-peroxidase complex method on paraffin blocks, applying S-100 protein, peptidylgylcine-alpha- hydroxylating monooxogenase and peptidyl-alpha- hydroxyglycine-alpha- amidating lyase as the first layer on paraffin serial sections. Chromaffin cells were positively stained by neuron-specific-enolase, 20/21 were positive for chromogranin, while sustentacular cells were negative. Sustentacular cells were positive for S-100 protein, while phaeochromocytes were negative. All sustentacular cells as well as Schwann cells were positive for S-100 protein and peptidylglycine-alpha- hydroxylating monooxogenase. The stain for the latter peptide was less intense, while chromaffin cells were all negative. Localization of peptidylglcine-alpha- hydroxylating monooxogenase in sustentacular cells suggest that these cells can produce amidating enzymes