title: A new bioactive form of human calcitonin.
abstract: Distinct immunoreactive forms of calcitonin (CT), extracted with 2 M acetic acid from two pancreatic tumors, were characterized and identified by gel permeation chromatography and by reverse-phase high-performance liquid chromatography. The extracted CT forms were compared to CT obtained from medullary thyroid carcinoma and from normal thyroid glands, and were, furthermore, analyzed in a rat hypocalcemic bioassay. On gel filtration analysis, two broad peaks coeluting with synthetic human CT-(1-32) and extracted dimeric CT, respectively, were found in variable amounts. An acetonitrile gradient high-performance liquid chromatography system revealed two to three predominant CT peaks. Biologically active monomeric and dimeric CT and the biologically inactive sulfoxide form of human CT-(1-32) have been identified. Moreover, we have detected for the first time a new biologically active CT-like component which was most prominently recognized in a benign pancreatic tumor.
mesh_terms: D000368:Aged; D000818:Animals; D001681:Biological Assay; D002116:Calcitonin / Q000032:analysis* / Q000494:pharmacology; D002118:Calcium / Q000097:blood; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D005260:Female; D006801:Humans; D008875:Middle Aged; D010190:Pancreatic Neoplasms / Q000032:analysis; D051381:Rats; D013961:Thyroid Gland / Q000032:analysis; D013964:Thyroid Neoplasms / Q000032:analysis
chemical_list: D002116:Calcitonin; D002118:Calcium