Expression of parathyroid hormone-related protein in abnormal human parathyroids

• Published in: Journal of endocrinology Vol. 129; no. 3; pp. 431 - 438
• Main Authors: DOCHERTY, H. M, RATCLIFFE, W. A, HEATH, D. A, DOCHERTY, K
• Format: Journal Article
• Language: English
• Published: Colchester BioScientifica 01.06.1991; Portland Press
• Subjects: Adenoma - genetics; Aminoacids, peptides. Hormones. Neuropeptides; Analytical, structural and metabolic biochemistry; Biological and medical sciences; Blotting, Northern; Carcinoma - genetics; Fundamental and applied biological sciences. Psychology; Gene Expression - physiology; Humans; Hyperplasia; Neoplasm Proteins - genetics; Parathyroid Diseases - genetics; Parathyroid Glands - chemistry; Parathyroid Glands - pathology; Parathyroid Hormone - analysis; Parathyroid Hormone - genetics; Parathyroid Hormone-Related Protein; Peptide Fragments - analysis; Peptides - analysis; Proteins; Proteins - analysis; Proteins - genetics; Radioimmunoassay; RNA, Messenger - analysis; Human; Northern blotting; Endocrine gland; Messenger RNA; Blotting assay; Parathyroid glands; Adenoma; Gene expression
• ISSN: 0022-0795; 1479-6805
• DOI: 10.1677/joe.0.1290431

ABSTRACT The expression of parathyroid hormone-related protein (PTHrP) in abnormal human parathyroids was investigated. Northern blot analysis of RNA extracted from human benign parathyroid adenomata (n = 4) revealed multiple PTHrP mRNA species ranging in size from 1·8 to 4kb. The relative abundance of PTHrP mRNA expressed in two of the adenomata was similar to that of a tumour (DAF) associated with humoral hypercalcaemia of malignancy, whereas PTHrP mRNA was of low abundance in a third and was undetectable in the fourth. PTHrP-like immunoreactivity was detected in extracts of abnormal parathyroid tissue (benign adenoma (n = 7), hyperplasia (n = 5) and parathyroid carcinoma (n = 2)) using a sensitive specific two-site immunoradiometric assay for human (h) PTHrP(1–86) and a radioimmunoassay for hPTHrP(1–34). Ratios of hPTHrP(1–86)- and hPTHrP(1–34)-like immunoreactivities relative to hPTH(1–84)-like immunoreactivity in the parathyroid tissue extracts were, on average, less than 1%. PTHrP bioactivity in the extracts could not be distinguished from that of PTH, by an osteosarcoma cell bioassay. We conclude that, despite reports of over-expression of PTHrP mRNA in parathyroid adenomata, the potential contribution of PTHrP to the total PTH-like activity of adenomata and other abnormal parathyroid tissue may be insignificant relative to PTH. Journal of Endocrinology (1991) 129, 431–438