The Mechanism of Human Placental Urea Transport: A Study Using Placental Brush Border (Microvillous) Membrane Vesicles

2010 ◽  
Vol 17 (1) ◽  
pp. 67-72 ◽  
Author(s):  
Hiroyasu Hisanaga ◽  
Hideaki Iioka ◽  
Ikuko Moriyama ◽  
Kaoru Nabuchi ◽  
Keiko Morimoto ◽  
...  
Keyword(s):  
Brush Border ◽  
Membrane Vesicles ◽  
Urea Transport ◽  
Microvillous Membrane Vesicles

Radiation inactivation studies of renal brush border water and urea transport

1985 ◽  
Vol 249 (6) ◽  
pp. F806-F812
Author(s):  
A. S. Verkman ◽  
J. A. Dix ◽  
J. L. Seifter ◽  
K. L. Skorecki ◽  
C. Y. Jung ◽  
...  
Keyword(s):  
Radiation Dose ◽  
Water Transport ◽  
Brush Border ◽  
Membrane Vesicles ◽  
Target Size ◽  
Freezing Process ◽  
Urea Transport ◽  
Transport Pathways ◽  
Radiation Inactivation ◽  
Osmotic Water

Radiation inactivation was used to determine the nature and molecular weight of water and urea transport pathways in brush border membrane vesicles (BBMV) isolated from rabbit renal cortex. BBMV were frozen to -50 degrees C, irradiated with 1.5 MeV electrons, thawed, and assayed for transport or enzyme activity. The freezing process had no effect on enzyme or transport kinetics. BBMV alkaline phosphatase activity gave linear ln(activity) vs. radiation dose plots with a target size of 68 +/- 3 kDa, similar to previously reported values. Water and solute transport were measured using the stopped-flow light-scattering technique. The rates of acetamide and osmotic water transport did not depend on radiation dose (0-7 Mrad), suggesting that transport of these substances does not require a protein carrier. In contrast, urea and thiourea transport gave linear ln(activity) vs. dose curves with a target size of 125-150 kDa; 400 mM urea inhibited thiourea flux by -50% at 0 and 4.7 Mrad, showing that radiation does not affect inhibitor binding to surviving transporters. These studies suggest that BBMV urea transport requires a membrane protein, whereas osmotic water transport does not.

Characterization of human placental activity for transport of taurocholate, using brush border (Microvillous) Membrane vesicles

Placenta ◽  
1993 ◽  
Vol 14 (1) ◽  
pp. 93-102 ◽  
Author(s):  
Hideaki Iioka ◽  
Hiroyasu Hisanaga ◽  
Shinobu Akada ◽  
Takako Shimamoto ◽  
Yoshihiko Yamada ◽  
...  
Keyword(s):  
Brush Border ◽  
Membrane Vesicles ◽  
Microvillous Membrane Vesicles

Characterization of human placental activity for transport of l.-alanine, using brush border (microvillous) membrane vesicles

Placenta ◽  
1992 ◽  
Vol 13 (2) ◽  
pp. 179-190 ◽  
Author(s):  
Hideaki Iioka ◽  
Hiroyasu Hisanaga ◽  
Ikuko S. Moriyama ◽  
Shinobu Akada ◽  
Takako Shimamoto ◽  
...  
Keyword(s):  
Brush Border ◽  
Membrane Vesicles ◽  
Microvillous Membrane Vesicles

Uptake ofl-carnitine by rat jejunal brush border microvillous membrane vesicles

1990 ◽  
Vol 35 (3) ◽  
pp. 333-339 ◽  
Author(s):  
B. U. K. Li ◽  
Paul M. Bummer ◽  
John W. Hamilton ◽  
Hallgrimur Gudjonsson ◽  
George Zografi ◽  
...  
Keyword(s):  
Brush Border ◽  
Membrane Vesicles ◽  
Microvillous Membrane Vesicles

Low-affinity transport of pyroglutamyl-histidine in renal brush-border membrane vesicles

1989 ◽  
Vol 257 (5) ◽  
pp. C971-C975 ◽  
Author(s):  
H. A. Skopicki ◽  
K. Fisher ◽  
D. Zikos ◽  
G. Flouret ◽  
D. R. Peterson
Keyword(s):  
Brush Border ◽  
Brush Border Membrane ◽  
Membrane Vesicles ◽  
Brush Border Membrane Vesicles ◽  
Proximal Tubular Cells ◽  
Tubular Cells ◽  
Luminal Membrane ◽  
Renal Brush Border Membrane ◽  
Proximal Tubular ◽  
Renal Brush Border

These studies were performed to determine if a low-affinity carrier is present in the luminal membrane of proximal tubular cells for the transport of the dipeptide, pyroglutamyl-histidine (pGlu-His). We have previously described the existence of a specific, high-affinity, low-capacity [transport constant (Kt) = 9.3 X 10(-8) M, Vmax = 6.1 X 10(-12) mol.mg-1.min-1] carrier for pGlu-His in renal brush-border membrane vesicles. In the present study, we sought to demonstrate that multiple carriers exist for the transport of a single dipeptide by determining whether a low-affinity carrier also exists for the uptake of pGlu-His. Transport of pGlu-His into brush-border membrane vesicles was saturable over the concentration range of 10(-5)-10(-3) M, yielding a Kt of 6.3 X 10(-5) M and a Vmax of 2.2 X 10(-10) mol.mg-1.min-1. Uptake was inhibited by the dipeptides glycyl-proline, glycyl-sarcosine, and carnosine but not by the tripeptide pyroglutamyl-histidyl-prolinamide. We conclude that 1) pGlu-His is transported across the luminal membrane of the proximal tubule by multiple carriers and 2) the lower affinity carrier, unlike the higher affinity carrier, is nonspecific with respect to other dipeptides.

Hydrolysis and transglycosylation activities of glycosidases from small intestine brush-border membrane vesicles

2021 ◽  
Vol 139 ◽  
pp. 109940
Author(s):  
Lesbia Cristina Julio-Gonzalez ◽  
F. Javier Moreno ◽  
María Luisa Jimeno ◽  
Elisa G. Doyagüez ◽  
Agustín Olano ◽  
...  
Keyword(s):  
Small Intestine ◽  
Brush Border ◽  
Brush Border Membrane ◽  
Membrane Vesicles ◽  
Brush Border Membrane Vesicles
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