Parathyroid hormone-related protein induced coupled increases in bone formation and resorption markers for 7 years in a patient with malignant islet cell tumors.

Abstract

Parathyroid hormone-related protein (PTHrP) and PTH share the common PTH/PTHrP receptor. Although an elevated level of circulating PTHrP in patients with malignancies causes hypercalcemia as does PTH, chronic and systemic effects of PTHrP on bone metabolism in humans are not well understood because tumor-burden patients showing hypercalcemia usually have a poor prognosis. We investigated bone and calcium metabolism in a patient with malignant islet cell tumors showing hypercalcemia due to the elevated plasma PTHrP level for 7 years. Hypercalcemia and hypercalciuria continued throughout the clinical course in spite of frequent infusions of bisphosphonates. Bone resorption markers and a bone formation marker were consistently elevated as seen in primary hyperparathyroidism, a disease caused by an autonomous hypersecretion of PTH. Based on biochemical measurements including bone markers and serum 1,25-dihydroxyvitamin D, the clinical features of this case essentially are the same as those of primary hyperparathyroidism except for the elevated level of plasma PTHrP with suppressed intact PTH level. Therefore, it is suggested that chronic and systemic effects of PTHrP on bone as well as calcium metabolism are indistinguishable from those of PTH in human.

• Authors: Yasuhiro Takeuchi, Seiji Fukumoto, Konosuke Nakayama, Yasuhiro Tamura, Akio Yanagisawa, Toshiro Fujita
• Journal: Journal of bone and mineral research : the official journal of the American Society for Bone and Mineral Research (J Bone Miner Res) Vol. 17 Issue 5 Pg. 753-7 (May 2002) ISSN: 0884-0431 [Print] United States
• PMID: 12009004 (Publication Type: Case Reports, Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Biomarkers
• PTHLH protein, human
• Parathyroid Hormone-Related Protein
• Peptide Hormones
• Calcitriol
• Calcium

Topics

• Adult
• Biomarkers
• Bone Resorption (etiology, metabolism)
• Bone and Bones (metabolism)
• Calcitriol (blood)
• Calcium (metabolism)
• Carcinoma, Islet Cell (complications, metabolism)
• Humans
• Hypercalcemia (etiology, metabolism)
• Male
• Osteogenesis (physiology)
• Pancreatic Neoplasms (complications, metabolism)
• Parathyroid Hormone-Related Protein
• Peptide Hormones (blood, metabolism)
• Time Factors