Sökning: onr:"swepub:oai:gup.ub.gu.se/107979" > Antagonistic effect...
Fältnamn | Indikatorer | Metadata |
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000 | 05301naa a2200361 4500 | |
001 | oai:gup.ub.gu.se/107979 | |
003 | SwePub | |
008 | 240910s2002 | |||||||||||000 ||eng| | |
024 | 7 | a https://gup.ub.gu.se/publication/1079792 URI |
024 | 7 | a https://doi.org/10.1677/jme.0.02800532 DOI |
040 | a (SwePub)gu | |
041 | a eng | |
042 | 9 SwePub | |
072 | 7 | a ref2 swepub-contenttype |
072 | 7 | a art2 swepub-publicationtype |
100 | 1 | a Larsson, Dennisu Gothenburg University,Göteborgs universitet,Zoologiska institutionen,Department of Zoology4 aut |
245 | 1 0 | a Antagonistic effects of 24R,25-dihydroxyvitamin D3 and 25-hydroxyvitamin D3 on L-type Ca2+ channels and Na+/Ca2+ exchange in enterocytes from Atlantic cod (Gadus morhua). |
264 | 1 | b Bioscientifica,c 2002 |
520 | a There is mounting evidence that vitamin D and its metabolites play important roles in regulating plasma calcium concentrations in teleost fish as in other vertebrates. The aims of the present study were to elucidate the possible cellular target mechanisms for the rapid actions of 24R,25(OH)(2)D(3), 25(OH)D(3) and 1,25(OH)(2)D(3) in Atlantic cod enterocytes at physiological doses, and to establish the concentration and thus the physiological range of circulating 24R,25(OH)(2)D(3), 25(OH)D(3) and 1,25(OH)(2)D(3) in the Atlantic cod. The plasma concentrations of 25(OH)D(3), 1,25(OH)(2)D(3) and 24R,25(OH)(2)D(3) were 15.3 +/- 2.7nM, 125.1 +/- 12.3pM and 10.1 +/- 23.5nM respectively. Exposure of enterocytes to 10mM calcium (Ca(2+)) evoked an increase in intracellular Ca(2+) concentrations ([Ca(2+)](i)). This increase was suppressed by 24R,25(OH)(2)D(3) dose-dependently, with an EC(50) of 4.9nM and a maximal inhibition of 60%. 24R,25(OH)(2)D(3) (20nM) abolished an increase in [Ca(2+)](i) (approximately 252%) in the control enterocytes exposed to 10microM S(-)-BAYK-8644, suggesting that the hormone acts by inhibiting Ca(2+) entry through L-type voltage-gated Ca(2+) channels. Administration of 20nM 24R,25(OH)(2)D(3) to enterocytes in the absence of extracellular Ca(2+) increased [Ca(2+)](i) by approximately 20%, indicating a release of Ca(2+) from intracellular stores. Administration of 25(OH)D(3) (20nM) resulted in a biphasic change in the enterocyte [Ca(2+)](i): within 1--5s, it decreased to 87 +/- 12nM below its mean basal [Ca(2+)](i) (334 +/- 13nM), followed by a rapid recovery of [Ca(2+)](i) to a new level, 10% lower than the initial [Ca(2+)](i). The rapid decrease, the recovery rate and the final [Ca(2+)](i) were all affected dose-dependently by 25(OH)D(3), with EC(50) values of 8.5, 17.0 and 18.9nM respectively. Furthermore, the effects of 25(OH)D(3) were sensitive to sodium (Na(+)), bepridil (10microM) and nifedipine (5 microM), suggesting that 25(OH)D(3) regulates the activity of both basolateral membrane-associated Na(+)/Ca(2+) exchangers and brush border membrane-associated L-type Ca(2+) channels. Administration of 25(OH)D(3) (10nM) to enterocytes in the absence of extracellular Ca(2+) increased [Ca(2+)](i) by approximately 18%, indicating a release of Ca(2+) from intracellular stores. 1,25(OH)(2)D(3) also affected enterocyte [Ca(2+)](i) in a biphasic manner: the rapid decrease, the recovery rate, and the mean final [Ca(2+)](i) were all affected dose-dependently, with EC(50) values of 8.3, 24.5 and 7.7nM respectively. The high EC(50) values for 1,25(OH)(2)D(3) compared with circulating concentrations of 1,25(OH)(2)D(3) (130pM) suggest that this effect is pharmacological, rather than of physiological relevance in enterocyte Ca(2+) homeostasis of the Atlantic cod. It is concluded that 24R,25(OH)(2)D(3) has a physiological role in decreasing intestinal Ca(2+) uptake via inactivation of L-type Ca(2+) channels, whereas the physiological role of 25(OH)D(3) is to increase enterocyte Ca(2+) transport via activation of Na(+)/Ca(2+) exchangers, concurrent with activation of L-type Ca(2+) channels. | |
650 | 7 | a MEDICIN OCH HÄLSOVETENSKAPx Klinisk medicinx Odontologi0 (SwePub)302162 hsv//swe |
650 | 7 | a MEDICAL AND HEALTH SCIENCESx Clinical Medicinex Dentistry0 (SwePub)302162 hsv//eng |
650 | 7 | a NATURVETENSKAPx Biologi0 (SwePub)1062 hsv//swe |
650 | 7 | a NATURAL SCIENCESx Biological Sciences0 (SwePub)1062 hsv//eng |
700 | 1 | a Aksnes, L4 aut |
700 | 1 | a Björnsson, Björn Thrandur,d 1952u Gothenburg University,Göteborgs universitet,Zoologiska institutionen,Department of Zoology4 aut0 (Swepub:gu)xbjorb |
700 | 1 | a Larsson, Birgittau Gothenburg University,Göteborgs universitet,Odontologiska institutionen,Institute of Odontology4 aut |
700 | 1 | a Lundgren, Ted,d 1959u Gothenburg University,Göteborgs universitet,Odontologiska institutionen,Institute of Odontology4 aut0 (Swepub:gu)xluted |
700 | 1 | a Sundell, Kristina,d 1959u Gothenburg University,Göteborgs universitet,Zoologiska institutionen,Department of Zoology4 aut0 (Swepub:gu)xskris |
710 | 2 | a Göteborgs universitetb Zoologiska institutionen4 org |
773 | 0 | t Journal of Molecular Endocrinologyd : Bioscientificag 28:1, s. 53-68q 28:1<53-68x 0952-5041x 1479-6813 |
856 | 4 | u https://jme.bioscientifica.com/downloadpdf/journals/jme/28/1/53.pdf |
856 | 4 8 | u https://gup.ub.gu.se/publication/107979 |
856 | 4 8 | u https://doi.org/10.1677/jme.0.0280053 |
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