Effect of dexamethasone on the lymphocytic Na+/H+ antiporter activity
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Effect of dexamethasone on the lymphocytic Na+/H+ antiporter activity. / Tepel, M; Pytlik, M; van der Giet, M; Schlüter, H; Jankowski, J; Zidek, W.
In: J HYPERTENS, Vol. 17, No. 11, 11.1999, p. 1553-6.Research output: SCORING: Contribution to journal › SCORING: Journal article › Research › peer-review
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TY - JOUR
T1 - Effect of dexamethasone on the lymphocytic Na+/H+ antiporter activity
AU - Tepel, M
AU - Pytlik, M
AU - van der Giet, M
AU - Schlüter, H
AU - Jankowski, J
AU - Zidek, W
PY - 1999/11
Y1 - 1999/11
N2 - OBJECTIVE: The effects of short-term administration of dexamethasone on sodium/proton antiporter (Na+/H+ antiporter) in human lymphocytes were investigated in vitro.METHODS: Cytosolic pHi in lymphocytes was measured spectrophotometrically using the pH-sensitive fluorescent dye 2'-7'-bis-carboxyethyl-5(6)-carboxyfluorescein at 530 nm with excitation wavelengths of 440 and 530 nm. The Na+/H+ antiporter activity was determined after intracellular acidification using 100 mmol/l propionic acid.RESULTS: The addition of 1 micromol/l dexamethasone significantly reduced cytosolic pHi from 7.44+/-0.03 to 7.25+/-0.05 (mean +/- SEM; P<0.01). Incubation with dexamethasone for 40 min significantly reduced the Na+/ H+ antiporter activity from (9.19+/-0.61)x10(-3) pHi/s (n = 22) to (7.23+/-0.49)x10(-3) pHi/s (n = 22; P<0.01). The effect of dexamethasone was time and concentration dependent The apparent affinity of the Na+/H+ antiporter was not significantly different in the absence or presence of dexamethasone. The inhibition of the Na+/H+ antiporter by dexamethasone was abolished in the presence of the glucocorticoid receptor blocker, mifepristone.CONCLUSION: Dexamethasone directly inhibits the Na+/H+ antiporter using a receptor-dependent pathway. This effect may be important for pharmacological side effects such as glucocorticoid-induced hypertension.
AB - OBJECTIVE: The effects of short-term administration of dexamethasone on sodium/proton antiporter (Na+/H+ antiporter) in human lymphocytes were investigated in vitro.METHODS: Cytosolic pHi in lymphocytes was measured spectrophotometrically using the pH-sensitive fluorescent dye 2'-7'-bis-carboxyethyl-5(6)-carboxyfluorescein at 530 nm with excitation wavelengths of 440 and 530 nm. The Na+/H+ antiporter activity was determined after intracellular acidification using 100 mmol/l propionic acid.RESULTS: The addition of 1 micromol/l dexamethasone significantly reduced cytosolic pHi from 7.44+/-0.03 to 7.25+/-0.05 (mean +/- SEM; P<0.01). Incubation with dexamethasone for 40 min significantly reduced the Na+/ H+ antiporter activity from (9.19+/-0.61)x10(-3) pHi/s (n = 22) to (7.23+/-0.49)x10(-3) pHi/s (n = 22; P<0.01). The effect of dexamethasone was time and concentration dependent The apparent affinity of the Na+/H+ antiporter was not significantly different in the absence or presence of dexamethasone. The inhibition of the Na+/H+ antiporter by dexamethasone was abolished in the presence of the glucocorticoid receptor blocker, mifepristone.CONCLUSION: Dexamethasone directly inhibits the Na+/H+ antiporter using a receptor-dependent pathway. This effect may be important for pharmacological side effects such as glucocorticoid-induced hypertension.
KW - Cytosol
KW - Dexamethasone
KW - Glucocorticoids
KW - Hormone Antagonists
KW - Humans
KW - Hydrogen-Ion Concentration
KW - Lymphocytes
KW - Mifepristone
KW - Osmolar Concentration
KW - Sodium-Hydrogen Exchangers
KW - Time Factors
KW - Journal Article
M3 - SCORING: Journal article
C2 - 10608467
VL - 17
SP - 1553
EP - 1556
JO - J HYPERTENS
JF - J HYPERTENS
SN - 0263-6352
IS - 11
ER -