On the Nature of Degradation of Calcitonin by Mammalian Cells

Abstract

Summary

By the use of immunological reactivity as an indicator, the degradation of synthetic human calcitonin was measured with cells isolated from rat kidney and bone after partial digestion with 0.3% crude collagenase. The degradation of the hormone by bone cells was undetectable (with up to 9 × 10⁵ cells per 0.5 ml). In contrast, renal cells degrade HCT readily. The degradation activity in renal cells appear to be cell bound. Measurement by specific radioimmunoassay of the degradation of HCT in the presence of SCT or PCT suggests competition between three different species of calcitonins for a possible common site of degradation not shared by other peptide hormones tested.