scholarly journals Ursodeoxycholate stimulates Na+-H+ exchange in rat liver basolateral plasma membrane vesicles.

1987 ◽  
Vol 80 (3) ◽  
pp. 684-690 ◽  
Author(s):  
R H Moseley ◽  
N Ballatori ◽  
D J Smith ◽  
J L Boyer
Keyword(s):  
Plasma Membrane ◽  
Rat Liver ◽  
Membrane Vesicles ◽  
Plasma Membrane Vesicles ◽  
Basolateral Plasma Membrane

scholarly journals Albumin binding of unconjugated [3H]bilirubin and its uptake by rat liver basolateral plasma membrane vesicles

1996 ◽  
Vol 316 (3) ◽  
pp. 999-1004 ◽  
Author(s):  
Lorella PASCOLO ◽  
Savino DEL VECCHIO ◽  
Ronald K. KOEHLER ◽  
J. Enrique BAYON ◽  
Cecile C. WEBSTER ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Rat Liver ◽  
Basolateral Membrane ◽  
Membrane Vesicles ◽  
Plasma Membrane Vesicles ◽  
Experimental Conditions ◽  
Saturation Kinetics ◽  
Basolateral Plasma Membrane ◽  
Component C ◽  
Uptake Studies

Using highly purified unconjugated [3H]bilirubin (UCB), we measured UCB binding to delipidated human serum albumin (HSA) and its uptake by basolateral rat liver plasma membrane vesicles, in both the absence and presence of an inside-positive membrane potential. Free UCB concentrations ([Bf]) were calculated from UCB–HSA affinity constants (K´f), determined by five cycles of ultrafiltration through a Centricon-10 device (Amicon) of the same solutions used in the uptake studies. At HSA concentrations from 12 to 380 μM, K´f (litre/mol) was inversely related to [HSA], irrespective of the [Bt]/[HSA] ratio. K´f was 2.066×106+(3.258×108/[HSA]). When 50 mM KCl was iso-osmotically substituted for sucrose, the K´f value was significantly lower {2.077×106+(1.099×108/[HSA])}. The transport occurred into an osmotic-sensitive space. Below saturation ([Bf] ⩽ 65 nM), both electroneutral and electrogenic components followed saturation kinetics with respect to [Bf], with Km values of 28±7 and 57±8 nM respectively (mean±S.D., n = 3, P < 0.001). The Vmax was greater for the electrogenic than for the electroneutral component (112±12 versus 45±4 pmol of UCB·mg-1 of protein·15 s-1, P < 0.001). Sulphobromophthalein trans-stimulated both electrogenic (61%) and electroneutral (72%) UCB uptake. These data indicate that: (a) as [HSA] increases, K´f decreases, thus increasing the concentration of free UCB. This may account for much of the enhanced hepatocytic uptake of organic anions observed with increasing [HSA]. (b) UCB is taken up at the basolateral membrane of the hepatocyte by two systems with Km values within the range of physiological free UCB levels in plasma. The electrogenic component shows a lower affinity and a higher capacity than the electroneutral component. (c) It is important to calculate the actual [Bf] using a K´f value determined under the same experimental conditions (medium and [HSA]) used for the uptake studies.

Taurocholate transport by basolateral plasma membrane vesicles isolated from developing rat liver

1985 ◽  
Vol 248 (6) ◽  
pp. G648-G654
Author(s):  
F. J. Suchy ◽  
S. M. Courchene ◽  
B. L. Blitzer
Keyword(s):  
Plasma Membrane ◽  
Rat Liver ◽  
Basolateral Membrane ◽  
Membrane Vesicles ◽  
Marker Enzyme ◽  
Marker Enzymes ◽  
Plasma Membrane Vesicles ◽  
Adult Rat ◽  
Basolateral Plasma Membrane ◽  
Taurocholate Transport

Taurocholate transport was characterized in basolateral plasma membrane vesicles prepared from the livers of 14-day-old Sprague-Dawley rats using a self-generating Percoll gradient method. Liver plasma membrane protein yield, intravesicular volume, and enrichments of various marker enzymes were similar to those obtained for vesicles from adult rat liver. The basolateral marker enzyme Na+-K+-ATPase was enriched 26-fold in the suckling rat basolateral membrane fraction while the bile canalicular marker enzymes alkaline phosphatase and Mg2+-ATPase were enriched only 3- and 5-fold, respectively. The activities of marker enzymes for endoplasmic reticulum, mitochondria, or lysosomes were not enriched compared with homogenate. In the presence of an inwardly directed 100 mM Na+ gradient, vesicle accumulation of taurocholate transiently reached a concentration 1.5- to 2-fold higher than that at equilibrium ("overshoot") in suckling and adult membrane vesicles, but the initial rate of taurocholate entry and peak intravesicular accumulation were markedly decreased in suckling compared with adult membrane vesicles. In the presence of an inwardly directed 100 mM K+ gradient, the rate of uptake was slower, and no overshoot occurred in either suckling or adult rat vesicles. The decreased rate of Na+-coupled taurocholate uptake by membrane vesicles from suckling rat liver could not be explained on the basis of more rapid dissipation of the transmembrane Na+ gradient. Kinetic studies demonstrated saturable, Na+-dependent taurocholate uptake for both suckling and adult vesicles. However, the Vmax for taurocholate uptake in suckling rat vesicles was less than half of the adult rate (2.46 +/- 0.13 vs. 5.25 +/- 0.22 nmol X mg prot-1 X min-1, respectively, P less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Uridine transport in basolateral plasma membrane vesicles from rat liver

1992 ◽  
Vol 128 (3) ◽  
Author(s):  
Bonaventura Ruiz-Montasell ◽  
F.Javier Casado ◽  
Antonio Felipe ◽  
Mar�al Pastor-Anglada
Keyword(s):  
Plasma Membrane ◽  
Rat Liver ◽  
Membrane Vesicles ◽  
Plasma Membrane Vesicles ◽  
Basolateral Plasma Membrane

Na(+)-H+ exchange in basolateral plasma membrane vesicles from neonatal rat liver

1990 ◽  
Vol 259 (3) ◽  
pp. G334-G339 ◽  
Author(s):  
A. L. Goodrich ◽  
F. J. Suchy
Keyword(s):  
Plasma Membrane ◽  
Rat Liver ◽  
Basolateral Membrane ◽  
Membrane Vesicles ◽  
Neonatal Rat ◽  
Plasma Membrane Vesicles ◽  
Adult Rat ◽  
Age Related ◽  
Basolateral Plasma Membrane ◽  
22Na Uptake

Basolateral plasma membrane vesicles (BLMV) were used to determine the activity of the Na(+)-H+ exchanger in neonatal compared with adult rat liver. Imposition of an outwardly directed H+ gradient (pH 5.5in/7.5out) markedly stimulated the uptake of 1 mM 22Na+ by adult and neonatal BLMV above rates observed under pH-equilibrated conditions (pH 7.5in/7.5out) and resulted in a transient uphill accumulation ("overshoot") of Na+ to levels 1.5- to 2-fold higher than at equilibrium. 22Na+ uptake via Na(+)-H+ exchange (identified as the amiloride-sensitive component of total Na+ flux) was greater in BLMV from neonatal compared with adult liver under both pH-gradient and -equilibrated conditions. These age-related differences in Na+ uptake could not be explained by membrane potential effects or by differences in membrane permeability to H+. Kinetic analysis revealed a saturable process with a similar Km for Na+ (8.6 +/- 1.6 vs. 8.1 +/- 1.5 mM) but with a 2.5-fold higher Vmax (8.06 +/- 0.67 vs. 3.20 +/- 0.40 nmol.mg protein-1.min-1; P less than 0.01) in neonatal vs. adult vesicles. We conclude from these studies that basolateral membrane vesicles from neonatal rat liver exhibit enhanced Na(+)-H+ exchange as a result of an increased number or translocation rate of carriers in the plasma membrane.

Taurocholate transport by basolateral plasma membrane vesicles isolated from human liver

Hepatology ◽  
1989 ◽  
Vol 10 (4) ◽  
pp. 447-453 ◽  
Author(s):  
Donald A. Novak ◽  
Frederick C. Ryckman ◽  
Frederick J. Suchy
Keyword(s):  
Plasma Membrane ◽  
Human Liver ◽  
Membrane Vesicles ◽  
Plasma Membrane Vesicles ◽  
Basolateral Plasma Membrane ◽  
Taurocholate Transport
Sign in / Sign up

Export Citation Format

Share Document