Parathyroid Growth

Overproduction of an amino‐terminal form of PTH distinct from human PTH(1–84) in a case of severe primary hyperparathyroidism: influence of medical treatment and surgery

“…level relative to the T-PTH level observed before surgery in this patient was related to the oversecretion of an amino-terminal (N) form of PTH recognized by PTH assays with (1)(2)(3)(4) or (26 -32) epitopes but not by the T-PTH assay with a (12)(13)(14)(15)(16)(17)(18) epitope. This molecular form represented 50% of CA-PTH measured in this patient, but only 7% in less severe cases of primary hyperparathyroidism.…”

“…Several aspects of this patient's condition at the initial presentation are worthy of discussion. The association of a large and rapidly growing parathyroid tumour with severe primary hyperparathyroidism and significant bone disease has been recognized as a different entity based on clinical criteria 1,2 . The role of vitamin D deficiency in the development of this class of patients remains unclear.…”

“…This is different from normal individuals made hypercalcaemic or from patients with non‐parathyroid hypercalcaemia who disclose a higher C‐PTH/I‐PTH ratio in the face of hypercalcaemia reflecting a higher output of C‐PTH fragments by their normally calcium‐sensitive parathyroid glands 9 . The second class of parathyroid tumours represent a minority of larger parathyroid tumours in very symptomatic patients, often presenting with osteitis fibrosa cystica 1,2 . Vitamin D deficiency, either primary 11,12 or secondary to high 25‐hydroxyvitamin D [25(OH)D] turnover 13 with low levels of 1,25(OH) 2 D related to inhibition of 1α‐hydroxylase activity arising from severe hypercalcaemia, 14–17 has been described in many cases.…”

“…Two classes of parathyroid tumour have been described based on both a theoretical and a clinical basis 1,2 . The first class occurs theoretically through a clonal expansion related to a higher set point of PTH stimulation by calcium while the second is presumed to derive through a different cellular abnormality producing rapid and sustained growth 1,2 . Most parathyroid adenoma are small parathyroid tumours in mildly symptomatic or asymptomatic patients 3 that belong to the first class.…”

A mathematical model of calcium and phosphorus metabolism in two forms of hyperparathyroidism

“…Besides the calcium and phosphorus balances in the serum and the urine, we also included two sub-compartments corresponding to the parathyroid glands and bone (bone forming osteoblasts and bone degrading osteoclasts). The rates of growth and degradation as well as the functional status of these compartments were subject to the regulatory factors (e.g., PTH, 1,25(OH) 2 D, calcium, and phosphorus) [3][4][5][6][7]. In interpreting clinical data, we used the procedure taken by Parfitt and co-workers [8][9][10][11][12][13].…”