Abstract
The extensive chromatographic characterization of four parathyroid hormone (PTH)-like proteins in a human bronchial carcinoid tumour associated with humoral hypercalcaemia and severe osteitis fibrosa is described. PTH-like bioactivity was detected in acetic acid extracts of the tumour using an in-vitro osteo-sarcoma cell bioassay. The active tumour proteins were positively charged at physiological pH and had apparent Mr of approximately 29,000, 16,000, 4000-9000 and less than 4000. The proteins were immunologically distinct from PTH, but each stimulated PTH-sensitive adenylate cyclase in cultured osteoblastic cells. There was no evidence of PTH gene expression by the tumour. These proteins represent different molecular forms of PTH-related protein.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Biological Assay
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Bronchial Neoplasms / analysis*
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Bronchial Neoplasms / complications
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Bronchial Neoplasms / genetics
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Carcinoid Tumor / analysis*
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Carcinoid Tumor / complications
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Carcinoid Tumor / genetics
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Carcinoid Tumor / secondary
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Cyclic AMP / biosynthesis
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DNA Probes
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Humans
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Hypercalcemia / complications
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Liver Neoplasms / analysis
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Liver Neoplasms / secondary
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Neoplasm Proteins / analysis*
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Neoplasm Proteins / genetics
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Nucleic Acid Hybridization
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Osteitis Fibrosa Cystica / complications
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Parathyroid Hormone / analysis*
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Parathyroid Hormone-Related Protein
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RNA, Neoplasm / analysis
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RNA, Neoplasm / genetics
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Trypsin / metabolism
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Tumor Cells, Cultured
Substances
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DNA Probes
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Neoplasm Proteins
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PTHLH protein, human
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Parathyroid Hormone
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Parathyroid Hormone-Related Protein
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RNA, Neoplasm
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Cyclic AMP
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Trypsin