Daily subcutaneous administration of bovine parathyroid hormone (PTH)(1-34) stimulates bone formation and increases bone mass in rat tibiae, femora and lumbar spine. However, the effects of PTH on the whole body bone mineral content and density determined by dual energy x-ray absortiometry (DEXA) have not been previously reported in rats. Eighteen-month-old intact female rats were subcutaneousl...

The metabolism of bovine parathyroid hormone (PTH) by the perfused rat liver was studied. Labeled hormone, with or without cold hormone, was infused into the circulating perfusion medium containing various calcium concentrations. Pefusate samples at various time periods after the introduction of PTH into the system were chromatographed on Bio-gel P-10; radioactivity and/or immunoreactivity were...

Cleavage of parathyroid hormone (PTH) by isolated Kupffer cells from rat liver was examined. Iodinated PTH labeled at position 43 was converted into two radioactive fragments which were shown by Edman degradation to have residues 35 and 38 as their NH2 termini. Cleavage at these positions is characteristic of cathepsin D. Amino-terminal fragments were detected by bioassay of fractions obtained ...

BACKGROUND The interest on magnesium (Mg) has grown since clinical studies have shown the efficacy of Mg-containing phosphate binders. However, some concern has arisen for the potential effect of increased serum Mg on parathyroid hormone (PTH) secretion. Our objective was to evaluate the direct effect of Mg in the regulation of the parathyroid function; specifically, PTH secretion and the expre...

Intermittent treatment with parathyroid hormone I(PTH) has an anabolic effect on both intact cancellous and cortical bone. Very little is known about the effect of the administration of PTH on the healing of fractures or the incorporation of orthopaedic implants. We have investigated the spontaneous ingrowth of callus and the formation of bone in a titanium chamber implanted at the medioproxima...

The effects of acetazolamide (Diamox), parathyroid hormone (PTH) and dibutyrylcyclic-adenosine 3':5'-monophosphate (db-cAMP) on fluid and 5,5-dimethyl-2,4-oxazolidinedione (DMO) absorption in the rat proximal convoluted tubule were studied by using microperfusion methods. The rate of tubular absorption of DMO was used to estimate the rate of hydrogen ion secretion. When the tubular and the peri...

The aim of this work was to optimize the absorption of parathyroid hormone 1-34 (PTH) from the lungs by determining factors favoring its transport from the air spaces into the bloodstream. We simultaneously conducted pharmacokinetic and regional lung deposition studies in vivo in the rat following intratracheal administration of PTH in solution or dry powder form. Dry powders of PTH or albumin ...

This annotation describes some early rat studies which conclude that parathyroid hormone (PTH) has more dramatic stimulatory effects on bone repair than on untraumatized bone. It also suggests, based on the effects of PTH on osteoblasts, that it is more likely to accelerate normal fracture healing than to prevent non-union. The only 2 controlled clinical trials that have been published are crit...

For the first time, PTH (1-34) was found to significantly affect bone quality, femora length, and body weight of aged, ovariectomized rats. Specifically, we examined the effects of biosynthetic human PTH (1-34) in 9 month-old rats that were ovariectomized and dosed for the ensuing 6 months with 8 or 40 microg/kg PTH. Bone content, architecture, and quality of axial and appendicular skeletal sit...

BACKGROUND AND PURPOSE Intermittent administration of parathyroid hormone (PTH) has an anabolic effect on bone, as confirmed in human osteoporosis studies, distraction osteogenesis, and fracture healing. PTH in rat models leads to improved fixation of implants in low-density bone or screw insertion transcortically. MATERIAL AND METHODS We examined the effect of human PTH (1-34) on the cancell...