We studied the effects of vitamin D metabolites on parathyroid hormone (PTH) secretion. Test materials were injected into the cranial thyroid artery of the dog, and immunoreactive PTH was measured frequently in serum samples from the inferior thyroid vein and the femoral vein. This model for the study of secretion had previously been validated with the use of known modulators on PTH secretion. ...

In mammals, parathyroid hormone (PTH) is a key regulator of extracellular calcium and inorganic phosphorus homeostasis. Although the parathyroid glands were thought to be the only source of PTH, extra-parathyroid PTH production in the thymus, which shares a common origin with parathyroids during organogenesis, has been proposed to provide an auxiliary source of PTH, resulting in a higher than e...

OBJECTIVE Smoking is associated with reduced bone density and calcium absorption, and reduced serum levels of vitamin D. A compensatory increase in serum parathyroid hormone (PTH) would therefore be expected as a result of an altered calcium balance. However, reports on PTH levels in smokers are conflicting. As serum PTH levels give important information on the calcium balance, the PTH levels i...

PTH and mechanical loading might act synergistically on bone formation. We tested the in vivo effect of the L-type voltage-sensitive calcium channel (VSCC) blocker, verapamil, on bone formation induced by human PTH-(1-34) (PTH) injection with or without mechanical loading. Adult rats were divided into eight groups: vehicle, verapamil, PTH, or verapamil plus PTH with or without mechanical loadin...

BACKGROUND In cross-sectional studies there appears to be a link between calcium metabolism and blood pressure, and most studies have found a positive association between serum parathyroid hormone (PTH) and hypertension. OBJECTIVE To determine the prognostic value of serum PTH regarding a future increase in blood pressure. DESIGN A prospective cohort study. SUBJECTS A total of 1784 indivi...

The performance and clinical utility of an automated assay of intact parathyroid hormone (parathyrin, PTH) are evaluated. The method is based on the extraction of PTH from plasma by an HPLC column containing immobilized anti-(44-68 PTH) antibodies. The PTH retained is detected with a postcolumn reactor and use of anti-(1-34 PTH) chemiluminescent-labeled antibodies. The total cycle time of the a...

The humoral hypercalcemia of malignancy (HHM) is caused by tumor cells that release a circulating factor which stimulates osteoclastic bone resorption. Recently, it has been reported that tumors associated with HHM contain factors that stimulate renal and bone cell adenylate cyclase. The activity was inhibited by parathyroid hormone (PTH) antagonists, and this led to the hypothesis that hyperca...

Specific degenerate codons in the amino-terminal region of a synthetic human parathyroid hormone (PTH) gene exerted dramatic effects on both products and yield of expression of this 84-amino acid polypeptide in Escherichia coli. With adenine-rich degenerate codons constituting the PTH-(1-5) region, intact PTH has been expressed as the only PTH product at 6.5 mg/liter. In contrast, with guanine-...

A 34-year-old female hemodialysis patient with an abnormal whole parathyroid hormone (PTH)/intact PTH ratio (ratio = 1.14) underwent parathyroidectomy for advanced secondary hyperparathyroidism. The abnormal PTH ratio indicated a relative increase in the serum N-terminus PTH, a new molecular form of PTH. The abnormal ratio normalized immediately after the largest parathyroid gland (PTG) was rem...

Circulating parathyroid hormone (PTH) regulates normal bone and mineral ion homeostasis and is central in the pathogenesis of bone disease in primary and secondary hyperparathyroidism, especially in advanced renal insufficiency (1 ). The major biological effects of PTH, a linear polypeptide 84 amino acids in length, reflect activation of the G-protein-coupled PTH/PTHrP receptor (PTHR) expressed...