Glucocorticoid regulation of amidating enzyme in a neoplastic C-cell line

Roger S. Birnbaum, Arthur H. Bertelsen, Bernard A. Roos

Research output: Contribution to journalArticlepeer-review

6 Scopus citations


Posttranslationar carboxyl-terminal amidation of many peptides is accomplished by peptidylglycine α-amidating monooxygenase. We have previously demonstrated that glucocorticoids stimulate production of amidated products by the CA-77 rat medullary thyroid carcinoma cell line. The present investigation was undertaken to determine whether amidation enzyme activity changes in parallel. Enzyme activity, similar to that found in other tissues, was readily detected in cell extracts and conditioned cultured medium. Stimulation with the calcitonin secretagogue calcium increased secretion of enzyme activity and lowered cell extract activity. Treatment of cultures with dexamethasone, but no other steroid, decreased by 50-70% the basal amidation enzyme activity secreted. There was no associated change in cellular activity. The decrease in medium activity was partially reversible and steroid-dose dependent. The glucocorticoid-induced change in medium activity was due to a decreased Vm. These experiments demonstrate that the a-amidating activity of the CA-77 cells can be hormonally regulated.

Original languageEnglish (US)
Pages (from-to)109-116
Number of pages8
JournalMolecular and Cellular Endocrinology
Issue number1
StatePublished - Jan 1989
Externally publishedYes


  • Amidation enzyme
  • C cell
  • Posttranslational processing enzyme

ASJC Scopus subject areas

  • Endocrinology
  • Endocrinology, Diabetes and Metabolism


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