Expression of Rho GDIα in rat osteoblasts intermittently exposed to parathyroid hormone in vitro and in vivo

Osteoblast-like cells prepared from calvaria of newborn rats produce insulin-like growth factor (IGF) I and several insulin-like growth factor binding proteins (IGFBPs) in vitro. Among the IGFBPs found in conditioned cell culture medium, IGFBP-3 is the most abundant. Intact IGFBP-3, as assessed by 125I-labeled IGF-II ligand blot analysis, is more abundant in culture media of cells exposed to growth hormone (GH) or to parathyroid hormone (PTH), both at 5 x 10(-9) mol/l, for 24 h. At the same time, concentrations of IGF-I are increased in media of cells exposed to PTH but not to GH, compared with hormone-free control cultures. IGFBP-3 mRNA is increased in osteoblasts exposed to PTH or to GH but not in response to 5 x 10(-9) mol/l IGF-I. PTH exerts a rapid (within 2 h) stimulatory effect on IGF-I and IGFBP-3 production, both at the message and peptide levels, whereas GH increases only IGFBP-3, both at the message and peptide levels (after 24 h). We conclude that IGF-I does not mediate increased IGFBP-3 production by rat osteoblasts in response to GH and PTH.

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Prolactin stimulation of parathyroid hormone secretion in bovine parathyroid cells

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.1984.247.5.e675 ◽

1984 ◽

Vol 247 (5) ◽

pp. E675-E680 ◽

Cited By ~ 1

Author(s):

L. Magliola ◽

L. R. Forte

Keyword(s):

Parathyroid Hormone ◽

Hormone Secretion ◽

Vitamin D Metabolism ◽

Parathyroid Function ◽

Wide Range ◽

Camp Levels ◽

Bovine Species ◽

Ca Homeostasis

Previous studies have suggested that prolactin (PRL) may affect calcium (Ca) homeostasis by an action on vitamin D metabolism. In this study, the effects of PRL on parathyroid hormone (PTH) secretion were investigated in dispersed bovine parathyroid cells (PTC). PRL (0.013-1.3 microM) caused concentration-dependent increases in PTH secretion. PRL-stimulated PTH release was apparent as early as 1 h and was progressive thereafter for up to 3 h. PRL enhanced PTH release over a wide range of ambient Ca concentrations (0.5-2.0 microM). Ovine and rat PRL were more effective than bovine PRL in stimulating PTH secretion. This effect was apparently specific for PRL because neither ovine nor bovine growth hormone stimulated PTH secretion. PRL-stimulated PTH release was not mediated through the beta-adrenergic or dopaminergic receptor systems of PTC and was not associated with increased adenosine 3',5'-cyclic monophosphate (cAMP) levels. This study demonstrated a direct effect of PRL to stimulate PTH secretion in vitro. Although these data do not provide evidence for an effect of PRL in vivo, we suggest a mechanism by which PRL may influence parathyroid function and Ca homeostasis in the bovine species.

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High-Affinity HLA-A(*)02.01 Peptides from Parathyroid Hormone-Related Protein Generate In Vitro and In Vivo Antitumor CTL Response Without Autoimmune Side Effects

The Journal of Immunology ◽

10.4049/jimmunol.169.9.4840 ◽

2002 ◽

Vol 169 (9) ◽

pp. 4840-4849 ◽

Cited By ~ 27

Author(s):

Guido Francini ◽

Antonio Scardino ◽

Kostas Kosmatopoulos ◽

François A. Lemonnier ◽

Giuseppe Campoccia ◽

...

Keyword(s):

Parathyroid Hormone ◽

Side Effects ◽

Related Protein ◽

Ctl Response ◽

High Affinity ◽

Parathyroid Hormone Related Protein

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Parathyroid hormone-related protein (PTHrP)-(1-139) isoform is efficiently secreted in vitro and enhances breast cancer metastasis to bone in vivo

Bone ◽

10.1016/s8756-3282(02)00685-3 ◽

2002 ◽

Vol 30 (5) ◽

pp. 670-676 ◽

Cited By ~ 64

Author(s):

T.A Guise ◽

J.J Yin ◽

R.J Thomas ◽

M Dallas ◽

Y Cui ◽

...

Keyword(s):

Breast Cancer ◽

Parathyroid Hormone ◽

Cancer Metastasis ◽

Breast Cancer Metastasis ◽

Related Protein ◽

Parathyroid Hormone Related Protein

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Effects of 1,25- and 24,25-dihydroxycholecalciferol on parathyroid hormone release from human parathyroid cells in vitro

Acta Endocrinologica ◽

10.1530/acta.0.1050354 ◽

1984 ◽

Vol 105 (3) ◽

pp. 354-359 ◽

Cited By ~ 4

Author(s):

Claes Rudberg ◽

Göran Åkerström ◽

Henry Johansson ◽

Sverker Ljunghall ◽

Jan Malmaeus ◽

...

Keyword(s):

Vitamin D ◽

Parathyroid Hormone ◽

Parathyroid Tissue ◽

Vitamin D Metabolites ◽

Hormone Release ◽

High Doses ◽

Parathyroid Hormone Release ◽

Dispersed Cells

Abstract. The effects of 125-dihydroxycholecalciferol (1,25-(OH)2D3) and 24,25-dihydroxycholecalciferol (24,25-(OH)2D3) on parathyroid hormone (PTH) release from human parathyroid cells were investigated using an in vitro system of dispersed cells. The cells were obtained from 7 patients with primary hyperparathyroidism (HPT) and adenoma, 4 patients with primary HPT due to hyperplasia and 2 patients with parathyroid hyperplasia secondary to chronic renal failure. The dispersed cells were incubated in tissue culture medium at low, normal and high external calcium concentrations for 2–16 h. There was a gradual suppression of PTH release (5–55%) when the calcium concentration in the medium was increased from 0.5 to 3.0 mM, thus indicating retained regulation of hormone release. The addition of 1,25-(OH)2D3 in concentrations of 0.1 and 1 ng/ml and of 24,25-(OH)2D3 in concentrations of 1.0 and 10 ng/ml during the incubations did not further affect the amount of PTH released by the cells. The concentrations of the different vitamin D metabolites tested closely correspond to levels observed under normal physiological conditions and during treatment with high doses of vitamin D in vivo. Thus, the findings contradict the idea of any direct short-term regulatory effect of either 1,25-(OH)2D3 or 24,25-(OH)2D3 on the secretion of PTH from hyperfunctioning human parathyroid tissue.

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Fluoride Modulates Parathyroid Hormone Secretion in vivo and in vitro

Cells Tissues Organs ◽

10.1159/000438699 ◽

2015 ◽

Vol 200 (6) ◽

pp. 413-423 ◽

Cited By ~ 8

Author(s):

Chaitanya P. Puranik ◽

Kathleen A. Ryan ◽

Zhaoyu Yin ◽

E. Angeles Martinez-Mier ◽

John S. Preisser ◽

...

Keyword(s):

Parathyroid Hormone ◽

Hormone Secretion

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Parathyroid hormone mRNA levels are increased by progestins and vary during rat estrous cycle

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.1996.270.1.e158 ◽

1996 ◽

Vol 270 (1) ◽

pp. E158-E163 ◽

Cited By ~ 1

Author(s):

E. Epstein ◽

J. Silver ◽

G. Almogi ◽

N. Livni ◽

T. Naveh-Many

Keyword(s):

Parathyroid Hormone ◽

Estrous Cycle ◽

Primary Cultures ◽

Parathyroid Tissue ◽

Ovariectomized Rats ◽

Mrna Levels ◽

Physiological Relevance ◽

Weanling Rats

Estrogen increases parathyroid hormone (PTH) mRNA levels in vivo in ovariectomized rats. We now show that the 19-norprogestin R-5020 given to weanling rats or mature ovariectomized rats led to a twofold increase in thyroparathyroid PTH mRNA levels. This increase in PTH mRNA occurred at 24 and 48 h after progesterone but not at 72 h. There were no changes in serum calcium. In vitro, in primary cultures of bovine parathyroid cells, progesterone increased PTH mRNA levels threefold at 10(-8) M and twofold at 10(-9) M after 24 h. Progesterone receptor (PR) mRNA was demonstrated in rat parathyroid tissue by in situ hybridization and in human parathyroid adenoma by immunohisto-chemistry. Changes in PTH mRNA levels during the rat estrous cycle were also studied. At proestrus and estrus PTH mRNA levels were increased significantly by three- and fourfold compared with diestrus. Our results confirm that the parathyroid gland is a target organ for the ovarian sex steroids estrogen and progesterone and are of physiological relevance as shown by the changes during estrus.

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