The spontaneously hypertensive rat (SHR) exhibits multiple abnormalities of calcium metabolism. Parathyroid hormone (PTH) has been shown to be a potent vasodilator in the SHR as well as other animal species. The current study assessed the influence of short-term manipulation of Ca + balance on PTH-induced vasodilation in the SHR. At 16 weeks of age, seven male SHRs were placed on a 0.02% Ca (de...

background: parathyroid hormone (pth) secreted by parathyroid glands regulates the metabolism of calcium and phosphorus in bone and kidney. thereby, it can stimulate bone formation, and is a promising agent in the treatment of osteoporosis. mature form of pth consists of 84 amino acids; however, the first 34 residues of pth cover the majority of hormonal action. methods: in this study, the fusi...

Mice in which the genes encoding the parathyroid hormone (PTH)-related peptide (PTHrP) or the PTH/PTHrP receptor have been ablated by homologous recombination show skeletal dysplasia due to accelerated endochondral bone formation, and die at birth or in utero, respectively. Skeletal abnormalities due to decelerated chondrocyte maturation are observed in transgenic mice where PTHrP expression is...

Regulation of vitamin D metabolism has long been examined by using vitamin D-deficient hypocalcemic animals. We previously reported that, in a rat model of chronic hyperparathyroidism, expression of 25-hydroxyvitamin D3-1alpha-hydroxylase (CYP27B1) mRNA was markedly increased in renal proximal convoluted tubules. It is believed that the major regulator for the expression of renal CYP27B1 is par...

BACKGROUND Both gastrectomy (GX) and ovariectomy (OVX) induce osteopenia in man and experimental animals. The present study addresses the question--can alendronate, estrogen or parathyroid hormone (PTH) be used to treat established GX- or OVX -evoked osteopenia? METHODS Rats were GX-, OVX- or SHAM-operated 8 weeks before starting the treatment with drugs. Each group was then treated for 8 wee...

Distraction osteogenesis is used both for leg lengthening and for bone transportation in the treatment of fractures and nonunions. The main problem with this method is that the time until full recovery may be up to a year, partly because of the time needed for the new formed bone to consolidate and become strong enough for weight bearing. We have studied whether intermittent parathyroid hormone...

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...

Phosphate homeostasis is maintained by a counterbalance between efflux from the kidney and influx from intestine and bone. FGF23 is a bone-derived phosphaturic hormone that acts on the kidney to increase phosphate excretion and suppress biosynthesis of vitamin D. FGF23 signals with highest efficacy through several FGF receptors (FGFRs) bound by the transmembrane protein Klotho as a coreceptor. ...

In this study we examined parathyroid hormone (PTH)-, forskolin (FSK)-, and cholera toxin (CTX)-stimulated adenosine 3',5'-cyclic monophosphate (cAMP) accumulation in rat osteoblastic cells (ROB) isolated from young (4 mo), mature (12 mo), and old (24-28 mo) male rats. Exposure to PTH increased cAMP accumulation in a concentration-dependent manner in all ROB cells examined. However, the maximum...