Calcitonin effects on isolated bone cells

  title={Calcitonin effects on isolated bone cells},
  author={Marc Shlossman and M J Brown and Eugenia Shapiro and R. Dziak},
  journal={Calcified Tissue International},
SummaryCalcitonin decreased calcium uptake in specific rat bone cell populations obtained by sequential collagenase digestions of calvaria. The calcitonin effect on calcium uptake was observed in the same populations that manifested calcitonin-induced increases in cyclic AMP as well as high levels of acid phosphatase and the ability to release45Ca from prelabeled devitalized bone. No effect of calcitonin was observed in cell populations that had high levels of alkaline phosphatase and lacked… 

Effects of tumor necrosis factor alpha on parathyroid hormone-induced increases in osteoblastic cell cyclic AMP

SummaryTumor necrosis factor α (10−10–10−8M) had no effects on cyclic AMP production by the osteoblastic osteosarcomal cells, Saos-2 and G292, or normal rat calvarial cells. The cytokine did,

Effects of leukotrienes on osteoblastic cell proliferation

The results suggest that LTB4 is involved in the regulation of osteoblastic cell proliferation and may interact with prostaglandins to modulate these effects.

Effects of inositol trisphosphate on calcium mobilization in bone cells

The results are consistent with the hypothesis that increases in IP3 can cause a rapid elevation of bone cell cytosolic calcium.

Recombinant interleukin-1 stimulates prostaglandin E2 production by osteoblastic cells: Synergy with parathyroid hormone

Recombinant mouse IL-1 (Interleukin-1) has been shown to be capable of stimulating prostaglandin E2 (PGE2) production by isolated rat osteoblastic cells in a dose-dependent manner, and Parathyroid hormone (PTH) appears to have a strong synergistic effect with IL- 1.

Insulin-like growth factors stimulate synthesis of nucleic acids and glycogen in cultured calvaria cells

SummaryA (sub)population of cells obtained from newborn rat calvaria by (sequential) collagenase digestion is grown to confluence in serum-containing medium. These cells are osteoblast-like with

Response of osteoblastic clonal cell line (MC3T3-E1) to [Asu1,7]Eel calcitonin at a specific cell density or differentiation stage

The results indicate that an increase in ALP activity by ECT is mediated by intracellular cAMP and that the specific response to ECT dependent on the cell density is regulated in the process of cAMP formation and/or in the preceding process ofcAMP formation.

Calcium currents in osteoblastic cells: Dependence upon cellular growth stage

The data suggest that the expression of VACC in the plasma membrane of rat calvarial osteoblasts depends on the time in culture and the state of proliferation of the cells.

Regulation of C-myc protooncogene expression in osteoblastic cells by arachidonic acid metabolites: Relationship to proliferation

The present studies show that prostaglandin E2 at 10-6 M decreased c-myc expression in these cells, and also inhibited proliferation of another human osteoblastic osteosarcoma cell line, Saos-2, but it did not produce any changes in c- myc expression.

Mechanisms of Thyroid Hormone-Induced Osteoporosis

Several new strategies for examining T3 effects on IGF-I and IL-6 gene expression, including the molecular reconstruction of the pathway in non-osteoblastic cells are being pursued.

Osteoporosis – a current view of pharmacological prevention and treatment

The current and future possibilities for identifying susceptible patients, from fracture risk assessment to shape modeling and in relation to the high heritability of osteoporosis are discussed, and the intimate relationship between the activities of bone forming and bone-resorbing cells is highlighted.



Separation of parathyroid hormone and calcitonin-sensitive cells from non-responsive bone cells

It has been demonstrated that exposure of mouse calvaria to PTH or CT can lead to an increase in cyclic AMP content and dibutyryl cyclicAMP can by itself induce bone resorption2.

Parathormone-stimulated resorption of devitalised bone by cultured osteoclast-type bone cells

It is found that parathormone markedly stimulated the capacity of CT, but not PT, cells to resorb a calcified bone matrix substrate—a property in keeping with the identification of the CT cells as osteoclasts.

Biochemical characterization with parathormone and calcitonin of isolated bone cells: provisional identification of osteoclasts and osteoblasts.

Two metabolically distinct types of bone cell populations were isolated from mouse calvaria by a repetitive digestive procedure with a mixture of collagenase and trypsin, and it is postulate that the CT type of populations is enriched in osteoclasts and, possibly, osteocytes, and the PT type of population is enrichment in osteoblasts.

The effect of calcium concentration on calcium uptake by bone cells treated with thyrocalcitonin (TCT) hormone.

The findings can be explained by assuming two types of calcium fluxes between medium and cells: a) a concentration dependent influx, and b) a constant rate calcium extrusion process subject to TCT inhibition.

Effect of phosphate, calcium and magnesium on bone resorption and hormonal responses in tissue culture.

Increasing the phosphate concentration of the medium over the range of 0.25 to 4M produced a decreased release of calcium from bone, particularly in response to parathyroid hormone, demonstrating that active resorption was inhibited.

The interaction of parathormone and calcium on the hormone-regulated synthesis of hyaluronic acid and citrate decarboxylation in isolated bone cells.

In the absence of parathormone, elevation of calcium concentration in the medium from a normal level of 1.8–5.8 mM mimicked the actions of parthormone on both biochemical activities as to maximum effect and time course and the change produced by calcium on hyaluronate synthesis was confined to osteoclast-like cells.

Calcium transport in isolated bone cells II. Calcium transport studies

Calcium transport was studied in bone cells isolated from fetal rat calvaria and uptake experiments revealed an active component of calcium exchange that appeared to be dependent on medium phosphate concentration.

Responses of fetal rat bone cells and bone organ cultures to the ionophore, A23187

At low concentrations, A23187 produced effects on bone similar to those of parathyroid hormone, suggesting that calcium is the primary initiator of PTH-induced bone resorption, and at the higher concentrations A23 187 may have a general inhibitory effect on cell metabolism.

Calcium transport in isolated bone cells. III. Effects of parathyroid hormone and cyclic 3',5'-AMP.

It is postulated that PTH increases the permeability of bone cell membranes to calcium by magnifying the effects of parathyroid hormone at 4 C, the membrane is relatively impermeable so the PTH effect is magnified.

Calcium transport in isolated bone cells I. Bone cell isolation procedures

Bone cells were isolated by collagenase‐hyaluronidase digestion of 19–20 day‐old fetal rat calvaria. It is shown that contamination from calcified matrix can give erroneously high values for total