The effects of osteoclast activating factor (OAF) released by normal human peripheral blood leukocytes cultured with phytohemagglutinin have been examined in organ culture. Like parathyroid hormone (PTH), OAF causes a rapid increased in the release of previously incorporated 45Ca from fetal rat bone after brief or continuous exposure; the bones also lose stable calcium and collagen content. The...

PTH is a potent bone anabolic factor, and its combination with antiresorptive agents has been proposed as a therapy for osteoporosis. We tested the effects of PTH, alone and in combination with the novel antiresorptive agent OPG, in a rat model of severe osteopenia. Sprague Dawley rats were sham-operated or ovariectomized at 3 months of age. Rats were untreated for 15 months, at which time ovar...

Chronic renal failure (CRF) is associated with a decrease in drug metabolism secondary to a decrease in liver cytochrome P450 (P450). The predominant theory to explain this decrease is the presence of factors in the blood of uremic patients. This study tested the hypothesis that parathyroid hormone (PTH) could be this factor. The objectives of this study were to determine (1) the role of PTH in...

The parathyroid hormone (PTH)/PTH-related peptide (PTHrP) receptor regulates extracellular calcium concentrations and is therefore important for mineral homeostasis. ROS 17/2.8 cells, a rat osteoblast-like osteosarcoma cell line, express the PTH/PTHrP receptor and provide a good model for examining the transcriptional regulation of its gene. The rat PTH/PTHrP receptor gene has two promoters, U1...

The biosynthetic pathway of parathyroid hormone (PTH) has been studied from gene expression to PTH intracellular processing.' The processing of PTH has been described and involves the synthesis of an initial translational product, preProPTH, and two proteolytic cleavages that in turn produce Pro PTH and PTH. The genes and cDNAs from ten different species have been cloned, sequenced and characte...

Parathyroid hormone (PTH) inhibits proximal tubular brush border membrane Na+/Pi cotransport activity; this decrease in the transport activity was found to be associated with a decrease in type II Na+/Pi cotransporter protein content in rat brush border membranes. In the present study we investigated the PTH-dependent regulation of the type II Na+/Pi cotransporter in opossum kidney cells, a pre...

The human parathyroid hormone (PTH) receptor (hPTH1R), containing a 9-amino acid sequence of rhodopsin at its C terminus, was transiently expressed in COS-7 cells and solubilized with 0.25% n-dodecyl maltoside. Approximately 18 microg of hPTH1R were purified to homogeneity per mg of crude membranes by single-step affinity chromatography using 1D4, a monoclonal antibody to a rhodopsin epitope. T...

BACKGROUND Some reports have shown that intermittent parathyroid hormone (PTH) (1-34) treatment for patients with delayed union or nonunion have led to successful healing. In this study, we investigated whether systemic intermittent administration of PTH (1-34) has a beneficial effect on bone healing in a rat refractory fracture model. METHODS We created a refractory femoral fracture model in...

BACKGROUND The aim of this study was to evaluate the effects of intermittent treatment of parathyroid hormone (PTH (1-34)) on the bone regeneration of critically-sized rat calvarial bone defects. MATERIAL AND METHODS Thirty-two male rats were trephined (4mm full-thickness diameter), in the central part of the parietal bones and divided into 2 groups of 16. The PTH group received subcutaneous ...

INTRODUCTION: Parathyroid hormone (PTH) is an 84 amino acid polypeptide that acts as the most important regulator of calcium homeostasis in the human body through its direct action on bone and kidney. Previously we reported that PTH(1-34) inhibits terminal differentiation of articular chondrocytes and in turn suppresses the progression of osteoarthritis (OA). However, the treatment needs the in...