ascorbic-acid and vanadium-diascorbate
ascorbic-acid has been researched along with vanadium-diascorbate* in 4 studies
Other Studies
4 other study(ies) available for ascorbic-acid and vanadium-diascorbate
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Interaction of [V
[VO(acac) Topics: Ascorbic Acid; Circular Dichroism; Humans; Models, Chemical; Organometallic Compounds; Quantum Theory; Serum Albumin; Spectrometry, Mass, Electrospray Ionization; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Transferrin | 2017 |
Inhibitors of Na-K-ATPase in human urine: effects of ouabain-like factors and of vanadium-diascorbate on calcium mobilization in rat vascular smooth muscle cells: comparison with the effects of ouabain, angiotensin II, and arginine-vasopressin.
Endogenous ouabain-like factors (OLF) may play a role in the pathogenesis of volume-dependent hypertension by raising intracellular free calcium ([Ca2+]i) as a consequence of inhibition of the sodium pump. In previous studies we described the presence of two low molecular (Mr approximately equals 400) inhibitors of Na-K-ATPase in human urine, ie, a more polar OLF-1 and a more apolar OLF-2. We subsequently identified the active compound in OLF-2 as vanadium (V(IV))-diascorbate (Mr 416). OLF-1, OLF-2, and V-diascorbate inhibited dose-dependently porcine Na-K-ATPase in vitro. In the present study we investigated the effects of urinary OLF-1, OLF-2, and V-diascorbate on calcium mobilization, ie, on [Ca2+]i in cultured rat vascular smooth muscle (VSM) cells in comparison to the effects of ouabain, angiotensin II (A II), and arginine-vasopressin (AVP). [Ca2+]i was determined by the fura-2 method. OLF-1 and OLF-2 (each approximately equals 10(-4) mol/L), obtained as single spots by thin-layer chromatography, produced a rise in [Ca2+]i in VSM cells from 45 +/- 7 to 99 +/- 22 and from 48 +/- 9 to 92 +/- 2 nmol/L (each n = 5; P < .05), respectively, after 3 min. V-diascorbate also increased [Ca2+]i slowly and dose-dependently, eg, from 56 +/- 14 to 102 +/- 15 nmol/L at a concentration of 10(-6) mol/L (n = 5; P < .05) after 3 min. A similar slow rise in [Ca2+]i from 53 +/- 10 to 185 +/- 3 nM (n = 5; P < .05) after 3 min was found with ouabain (10(-6) mol/L). As standard vasoconstrictor, All (10(-8) mol/L) rapidly increased [Ca2+]i from 23 +/- 4 to 846 +/- 50 nmol/L (n = 7; P < .01) within 30 sec. This effect was enhanced to 1,389 +/- 161 nM (n = 7; P < .01) when VSM cells were preincubated with V-diascorbate (10(-6) mol/L) for 10 min. AVP (10(-7) mol/L) also rapidly increased [Ca2+]i to 418 +/-11 nmol/L within 30 sec (n = 7; P < .01). This effect was enhanced in the presence of OLF-2 (approximately equals 10(-4) mol/L) or ouabain (10(-6) mol/L) to 523 +/- 14 and 560 +/- 19 nmol/L, respectively (each n = 7); P < .01). The calcium channel blocker verapamil, the intracellular calcium release blocker TMB-8, and the unselective cation channel blocker Ni2+ partly blunted the A II- or AVP-induced rise in [Ca2+]i and prevented the OLF-2- and V-diascorbate-induced increase in [Ca2+]i. Thus, OLF-1, OLF-2 and V-diascorbate, the active component of OLF-2, reveal effects similar to those of ouabain on [Ca2+]i in VSM cells, ie, they produce a slow rise in [Ca2+]i subsequent to in Topics: Adult; Angiotensin II; Animals; Aorta, Thoracic; Arginine Vasopressin; Ascorbic Acid; Biological Factors; Biological Transport; Calcium; Calcium Channel Blockers; Cardenolides; Cells, Cultured; Digoxin; Enzyme Inhibitors; Gallic Acid; Humans; Hypertension, Renal; Male; Muscle, Smooth, Vascular; Nickel; Organometallic Compounds; Ouabain; Rats; Saponins; Sodium-Potassium-Exchanging ATPase; Vasoconstrictor Agents; Verapamil | 2000 |
Effects of urinary ouabain-like factors and vanadium diascorbate on calcium mobilization in porcine inner medullary collecting duct cells: comparison with the effects of ouabain and vasopressin.
It is speculated that ouabain-like factors (OLF) play a role in the pathogenesis of volume-dependent hypertension. In previous studies we isolated a more polar OLF-1 and a more apolar OLF-2 from the urine of healthy subjects after 5 days on a high sodium intake (>400 mmol/day) by gel chromatography (Sephadex G-25 and G-10) and reverse-phase HPLC. We subsequently identified the chemical structure of OLF-2 as vanadium (V(IV)) diascorbate. OLF-1, OLF-2, and vanadium diascorbate inhibited dose-dependently porcine Na-K-ATPase in vitro. Because the inner medullary collecting duct (IMCD) plays a crucial role in the long-term regulation of body fluid volume, in the present study we investigated the effects of urinary OLF-1 and OLF-2, and of vanadium diascorbate in comparison to ouabain and vasopressin (AVP) on calcium mobilization, ie, on free calcium concentration [Ca2+]i, in cultured porcine IMCD cells. [Ca2+]i was determined by the fura-2 method in IMCD cells isolated by hypotonic treatment and density gradient centrifugation from fresh porcine kidneys. Assuming an approximate molecular weight (MW) of 400 for OLF-1 and OLF-2, OLF-1 (10(-4) mol/L) produced a slow increase in [Ca2+]i from 39 +/- 10 to 169 +/- 21 nmol/L (n = 7 ) after 4 min. Similarly, OLF-2 (10(-4) mol/L) resulted in an increase in [Ca2+]i from 74 +/- 20 to 216 +/- 52 nmol/L (n = 7) after 4 min. Vanadium diascorbate (MW 403) dose-dependently increased [Ca2+]i . At a concentration of 10(-6) mol/L it increased [Ca2+]i from 46 +/- 5 to 149 +/- 9 nmol/L (n = 5) after 4 min. A similar slow increase in [Ca2+]i was found with ouabain (10(-6) mol/L), which increased [Ca2+]i from 61 +/- 22 to 180 +/- 29 nmol/L (n = 5) after 4 min in contrast to AVP (10(-7) mol/L), which rapidly increased [Ca2+]i from 48 +/- 10 to 299 +/- 32 nmol/L (n = 4) within 30 sec. Thus, OLF-1, OLF-2, and Vanadium diascorbate, the active component of OLF-2, reveal similar effects as ouabain on IMCD cells, ie, they produce a slow increase in [Ca2+]i as expected from inhibition of Na-K-ATPase. The physiologic or pathologic roles of these and additional OLF in body fluid and blood pressure regulation and in hypertension have yet to be evaluated. Topics: Adult; Animals; Arginine Vasopressin; Ascorbic Acid; Biological Factors; Biological Transport; Calcium; Calcium Channel Blockers; Cells, Cultured; Gallic Acid; Humans; Kidney Medulla; Kidney Tubules, Collecting; Male; Organometallic Compounds; Ouabain; Renal Agents; Swine; Verapamil | 1998 |
Vanadium-diascorbates are strong candidates for endogenous ouabain-like factors in human urine: effects on Na-K-ATPase enzyme kinetics.
Recently, we isolated from the urine of salt-loaded healthy subjects a more polar ouabain-like factor OLF-1 and a more apolar OLF-2, the latter cross-reacted with a digoxin anti-body. They were purified to single compounds with dose-dependent Na-K-ATPase inhibition. Mass-spectroscopy (MS) showed a Mr of around 400 and 1H-NMR- and IR-spectroscopy suggested diascorbic acid salts, i.e., vanadium (V) diascorbates (Mr 403) with similar elution times from RP-HPLC as OLFs. IC50 was 9 x 10(-5)M for VIV-diascorbate as compared to 2 x 10(-6)M for Vv-diascorbate. Enzyme inhibition was non-competitive with respect to sodium and Mg-ATP; p-NPPase assay showed strong inhibition in its E2-configuration. We suggest that V-diascorbates represent endogenous OLFs excreted in human urine. Topics: 4-Nitrophenylphosphatase; Animals; Ascorbic Acid; Ca(2+) Mg(2+)-ATPase; Cations, Divalent; Cerebral Cortex; Chromatography, High Pressure Liquid; Humans; Kinetics; Magnetic Resonance Spectroscopy; Mass Spectrometry; Organometallic Compounds; Ouabain; Sodium-Potassium-Exchanging ATPase; Sodium, Dietary; Spectrophotometry, Infrared; Swine | 1995 |