Potassium channel activator bl-1249 inhibits the c-fos response to parathyroid hormone in osteoblastic cells in a dose-dependent manner

Bone ◽  
2009 ◽  
Vol 44 ◽  
pp. S304
Author(s):  
A.W. Gallagher ◽  
J.M. Quayle ◽  
J.A. Gallagher⁎
Keyword(s):  
Parathyroid Hormone ◽  
Potassium Channel ◽  
Osteoblastic Cells ◽  
Dependent Manner ◽  
Potassium Channel Activator ◽  
Dose Dependent ◽  
Channel Activator

scholarly journals Genistein modulates the effects of parathyroid hormone in human osteoblastic SaOS-2 cells

2006 ◽  
Vol 95 (6) ◽  
pp. 1039-1047 ◽  
Author(s):  
Wen-Fang Chen ◽  
Man-Sau Wong
Keyword(s):  
Parathyroid Hormone ◽  
Mrna Expression ◽  
Osteoblastic Cells ◽  
Dependent Manner ◽  
Alp Activity ◽  
Rankl Mrna ◽  
Receptor Activator ◽  
Pre Treatment ◽  
Dose Dependent ◽  
Rankl Mrna Expression

Genistein and parathyroid hormone (PTH) are anabolic agents that stimulate bone formation through their direct actions in osteoblastic cells. In the present study, we aimed to determinewhether genistein modulates the actions of PTH in human osteoblastic SaOS-2 cells in an oestrogen-depleted condition. The present results showed that genistein (10−8to 10−6m) induced alkaline phosphatase (ALP) activity and osteoprotegrin (OPG) expression in SaOS-2 cells in a dose-dependent manner. These effects could be completely abolished by co-treatment with oestrogen antagonist ICI 182780 (7α-[9-[(4,4,5,5,5-pentafluoropentyl)sulfonyl]nonyl]-estra-1,3,5(10)-triene-3,17β-diol). Genistein (at 1μm) could stimulate the mRNA expression of receptor activator of NF-κB ligand (RANKL). As OPG and RANKL are known to modulate osteoclastogenesis, the ability of genistein to modulate OPG and RANKL expression in SaOS-2 cells suggested that it might modulate osteoclastogenesis through its direct actions on osteoblastic cells. PTH (at 10nm) stimulated ALP activity, induced RANKL mRNA expression and suppressed OPG mRNA expression in SaOS-2 cells, confirming its bi-directional effects on osteoblastic cells. Pre-treatment of SaOS-2 cells with genistein andoestrogen not only enhanced PTH-induced ALP activity, but also attenuated PTH up regulation ofRANKL mRNA expression and PTH down regulation of OPG mRNA expression. Taken together, the present study provides the first evidence that genistein could modulate the actions of PTH in human osteoblastic SaOS-2 cells in an oestrogen-depleted condition.

scholarly journals Nicorandil-Induced Hyperkalemia in a Uremic Patient

2012 ◽  
Vol 2012 ◽  
pp. 1-4 ◽  
Author(s):  
Hung-Hao Lee ◽  
Po-Chao Hsu ◽  
Tsung-Hsien Lin ◽  
Wen-Ter Lai ◽  
Sheng-Hsiung Sheu
Keyword(s):  
Potassium Channel ◽  
Potassium Ions ◽  
Uremic Patient ◽  
Membrane Hyperpolarization ◽  
Voltage Gated ◽  
Antianginal Agent ◽  
Voltage Gated Calcium Channels ◽  
Detailed Evaluation ◽  
Potassium Channel Activator ◽  
Channel Activator

Nicorandil is an antianginal agent with nitrate-like and ATP-sensitive potassium channel activator properties. After activation of potassium channels, potassium ions are expelled out of the cells, which lead to membrane hyperpolarization, closure of voltage-gated calcium channels, and finally vasodilation. We present a uremic case suffering from repeated junctional bradycardia, especially before hemodialysis. After detailed evaluation, nicorandil was suspected to be the cause of hyperkalemia which induced bradycardia. This case reminds us that physicians should be aware of this potential complication in patients receiving ATP-sensitive potassium channel activator.

Endothelium-Derived Hyperpolarizing Factor (EDHF): An Endogenous Potassium-Channel Activator

Physiology ◽  
1990 ◽  
Vol 5 (5) ◽  
pp. 212-215
Author(s):  
H Suzuki ◽  
G Chen
Keyword(s):  
Potassium Channel ◽  
Smooth Muscles ◽  
Vascular Smooth Muscles ◽  
Membrane Hyperpolarization ◽  
Potassium Permeability ◽  
Potassium Channel Activator ◽  
Endothelium Dependent Relaxation ◽  
Channel Activator

Acetylcholine hyperpolarizes the membrane of vascular smooth muscles by increasing potassium permeability, the response being mediated by an endothelium-derived hyperpolarizing factor (EDHF). The membrane hyperpolarization produced by EDHF is therefore one of the components contributing to endothelium-dependent relaxation of vascular smooth muscles.

scholarly journals Calcium rather than cyclic AMP is an intracellular messenger of parathyroid hormone action on glycogen metabolism in isolated rat hepatocytes

1989 ◽  
Vol 258 (3) ◽  
pp. 889-894 ◽  
Author(s):  
T Mine ◽  
I Kojima ◽  
E Ogata
Keyword(s):  
Parathyroid Hormone ◽  
Cyclic Amp ◽  
Glucose Production ◽  
Rat Hepatocytes ◽  
Free Calcium ◽  
Dependent Manner ◽  
Isolated Rat Hepatocytes ◽  
Glucose Output ◽  
Dose Dependent ◽  
Isolated Rat

The synthetic 1-34 fragment of human parathyroid hormone (1-34hPTH) stimulated glucose production in isolated rat hepatocytes. The effect of 1-34hPTH was dose-dependent and 10(10) M-1-34 hPTH elicited the maximum glucose output, which was approx. 80% of that by glucagon. Although 1-34hPTH induced a small increase in cyclic AMP production at concentrations higher than 10(-9) M, 10(-10) M-1-34hPTH induced the maximum glucose output without significant elevation of cyclic AMP. This is in contrast to the action of forskolin, which increased glucose output to the same extent as 10(-10) M-1-34hPTH by causing a 2-fold elevation of cyclic AMP. In addition to increasing cyclic AMP, 1-34hPTH caused an increase in cytoplasmic free calcium concentration ([Ca2+]c). When the effect of 1-34hPTH on [Ca2+]c was studied in aequorin-loaded cells, low concentrations of 1-34hPTH increased [Ca2+]c: the 1-34hPTH effect on [Ca2+]c was detected at as low as 10(-12) M and increased in a dose-dependent manner. 1-34hPTH increased [Ca2+]c even in the presence of 1 microM extracellular calcium, suggesting that PTH mobilizes calcium from an intracellular pool. In line with these observations, 1-34hPTH increased the production of inositol trisphosphate. These results suggest that: (1) PTH activates both cyclic AMP and calcium messenger systems and (2) PTH stimulates glycogenolysis mainly via the calcium messenger system.

Cardiovascular Profile of RWJ 29009, a New Potassium Channel Activator, in Anesthetized and Conscious Dogs

1994 ◽  
Vol 2 (2) ◽  
pp. 300-310
Author(s):  
Bruce P. Damiano ◽  
Edward C. Giardino ◽  
Barbara J. Haertlein ◽  
Gary L. Stump ◽  
John A. Mitchell ◽  
...  
Keyword(s):  
Potassium Channel ◽  
Conscious Dogs ◽  
Potassium Channel Activator ◽  
Cardiovascular Profile ◽  
Channel Activator
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